Summary of Significant Accounting Policies - Leveraged Leases (Details) - Domestic And International Leveraged Lease [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Investments from Leveraged Lease
Net rentals receivable	$ 1,487	$ 1,495
Unearned income	(732)	(752)
Investment in leveraged leases	755	743
Deferred taxes from leveraged leases	(303)	(299)
Net investment in leveraged leases	452	444
Components of Income from Leveraged Lease
Pretax leveraged lease income (loss)	20	24	$ (5)
Income tax expense	(7)	(9)	2
Net leveraged lease income (loss)	$ 13	$ 15	$ (3)