RESTRUCTURING

The following table shows the balances and activity for restructuring charges:



(in millions)	Severance and Related Costs			Lease Restructuring
Liability as of January 1, 2015	$	42		$	462
Additional costs and expenses	8			36
Payments	(27		)	(63		)
Liability as of September 30, 2015	$	23		$	435

Fleet and other. We continue to restructure our domestic fleet by replacing a portion of our 50-seat regional fleet with more efficient and customer preferred CRJ-900 and B-717-200 aircraft and by replacing older, less cost effective B-757-200 with B-737-900ER aircraft. The lease restructuring charges include remaining lease payments and lease return costs for permanently grounded aircraft.

As we continue to restructure our 50-seat regional fleet and assess our fleet plans, we may evaluate and adjust the expected size of the remaining active regional fleet. A decrease in the expected remaining fleet may cause us to retire additional aircraft, which would likely result in lease termination and other charges. The timing and amount of these charges will depend on a number of factors, including final negotiations with lessors, the timing of removing the aircraft from service and the ultimate disposition of aircraft.

Severance and related costs. In September 2015, we announced a voluntary retirement program for eligible U.S. employees. We will record a charge in connection with this program when voluntary severance commitments are finalized during the December 2015 quarter.