Derivative and Hedging Activities - Components of Interest Income and Interest Expense Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest expense on senior notes	$ 588	$ 682	$ 704
Interest expense on term loan	46	0	36
Amortization of loan discount, issuance costs and other	33	62	42
Amortization of premium associated with troubled debt restructuring	(165)	(3)	0
Interest expense on revolving credit facilities	35	12	28
Gains on terminated fair value hedges	(2)	(3)	(3)
(Gains) losses on undesignated interest rate derivatives	12	(9)	(81)
Capitalized interest	(251)	(424)	(637)
Total interest expense	$ 296	$ 317	$ 89