Restructuring and Other - Schedule of Amounts Recorded on Consolidated Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	$ 0	$ 35	$ 716
Fleet and other
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	0	35	758
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	0	0	71
Settlements
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	$ 0	$ 0	$ 113