National Security & Digital revenues of $1.87 billion increased by 1% compared to the prior year quarter. Revenue grew across several enterprise Information Technology (IT) programs, which offset reductions on certain Intelligence Community contracts. For the quarter, operating income margin increased to 10.0% from 9.2% in the prior year quarter, and non-GAAP operating income margin increased to 10.5% from 9.8% in the prior year quarter. The increase in segment profitability was primarily attributable to volume and efficiencies on certain fixed price programs.

Health & Civil

Health & Civil revenues of $1.23 billion increased by 16% compared to the prior year quarter. Health & Civil operating income margin for the quarter was 23.4%, compared to 15.6% in the prior year quarter, and non-GAAP operating income margin was 24.2%, compared to 16.5% in the prior year quarter. The increase in revenues and segment profitability was driven by increased volumes and case complexity within the managed health services business as well as net write-ups on certain programs.

Commercial & International

Commercial & International revenues of $578 million increased by 5% compared to the prior year quarter driven by increased deliveries of security products and commercial energy engineering services. Operating income margin for the quarter was 7.1%, compared to (117.0)% in the prior year quarter, which included non-cash impairment and restructuring charges of $679 million related to the SES reporting unit. Non-GAAP operating margin was 8.8%, compared to 9.2% in the prior year quarter.

Defense Systems

Defense Systems revenues of $522 million increased by 13% compared to the prior year quarter. Defense Systems operating income margin for the quarter was 7.1%, compared to 0.6% in the prior year quarter, and non-GAAP operating margin was 10.2%, compared to 7.4% in the prior year quarter. The increase in revenues and segment profitability was primarily driven by increased scope and improved program execution on fixed price development programs.

LEIDOS HOLDINGS, INC.
UNAUDITED BACKLOG BY REPORTABLE SEGMENT
(in millions)

Backlog represents the estimated amount of future revenues to be recognized under negotiated contracts. Backlog value is based on management's estimates about volume of services, availability of customer funding and other factors, and excludes contracts that are under protest. Estimated backlog comprises both funded and negotiated unfunded backlog. Backlog estimates are subject to change and may be affected by several factors, including modifications of contracts, non-exercise of options and foreign currency movements.

Funded backlog for contracts with the U.S. government represents the value on contracts for which funding is appropriated less revenues previously recognized on these contracts. Funded backlog for contracts with non-U.S. government entities and commercial customers represents the estimated value on contracts, which may cover multiple future years, under which Leidos is obligated to perform, less revenue previously recognized on the contracts.

Negotiated unfunded backlog represents estimated amounts of revenue to be earned in the future from contracts for which funding has not been appropriated and unexercised priced contract options. Negotiated unfunded backlog does not include unexercised option periods and future potential task orders expected to be awarded under IDIQ, General Services Administration Schedule or other master agreement contract vehicles, with the exception of certain IDIQ contracts where task orders are not competitively awarded or separately priced but instead are used as a funding mechanism, and where there is a basis for estimating future revenues and funding on future anticipated task orders.

The estimated value of backlog as of the dates presented was as follows:

LEIDOS HOLDINGS, INC.