As is typical in the defense authorization process, House and Senate lawmakers made differing choices over key policy and military hardware issues. Both bills, however, would adhere to the $514 billion discretionary cap for fiscal 2015 Pentagon base spending established by the Ryan-Murray budget.

Perhaps the most substantial difference between the two bills lies with the Overseas Contingency Operations account, which the White House did not formally request until June. The House Armed Services Committee instead marked up its bill based on the administration’s placeholder value of $79.4 billion, while the Senate did not include the OCO funds at all.

The formal administration OCO request totaled $59.7 billion, including $1 billion for a European Reassurance Initiative and another $5 billion for a Counterterrorism Partnership Fund, which initially drew criticism from lawmakers. But with air strikes and other operations to combat the Islamic State in Iraq costing, on average, $7.5 million a day, the requested amount may not be enough to cover military operations in Middle East as well as in Afghanistan.

As with last year’s legislation, the Republican House and Democratic Senate differ on detainees held at Guantánamo Bay, Cuba. The House bill (HR 4435) would bar the transfer of detainees currently held at Guantánamo to the United States for imprisonment.

The Senate bill (S 2410), however, includes a pathway for closing Guantánamo. The legislation would permit the transfer of detainees to the U.S. after the president submits a plan to Congress for closing the detention center while also giving Congress authority to vote to disapprove that plan.

The appeal of the Senate’s detainee language may have waned among lawmakers following sharp criticism from members of both parties that the administration failed to notify Congress before it struck a deal to trade five Taliban detainees for the release of Army Sgt. Bowe Bergdahl.

Both bills would reject many contentious cost savings proposed by the military — including changes to Tricare and another round of base closures. Other highlights:

The Senate bill would accept a proposal to deactivate 11 Ticonderoga class cruisers — half the fleet — for modernization, which the Navy says would extend the ships’ life spans into the 2040s. The House bill would bar the deactivations.

With an aim to wind down production, the Navy requested just $43.5 million for the E/A-18G Growler electronic attack aircraft program in fiscal 2015. Senators would instead authorize $100 million to keep the production lines running, while the House measure would authorize an additional $450 million to buy five additional planes.

Both bills also would prohibit the Air Force proposal to retire the A-10 Thunderbolt II close-air support aircraft, commonly known as the “Warthog,” to save an estimated $4.2 billion over the next five years. The House bill would tap overseas contingency operations funding to the tune of $635 million to keep the aircraft flying in fiscal 2015, while the Senate bill provides $320 million offset by unspecified spending cuts elsewhere.