Restructuring and Other - Schedule of Restructuring Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Severance and related costs
Restructuring Reserve
Liability at beginning of period	$ 52	$ 42	$ 0
Additional costs and expenses	11	51	71
Payments	(59)	(41)	(29)
Other	0	0	0
Liability at end of period	4	52	42
Lease restructuring
Restructuring Reserve
Liability at beginning of period	415	462	168
Additional costs and expenses	1	41	349
Payments	(85)	(86)	(55)
Other	(2)	(2)	0
Liability at end of period	$ 329	$ 415	$ 462