Derivative and Hedging Activities - Components of Interest Income and Interest Expense Table (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest expense on senior notes	$ 136	$ 157
Interest expense on term loan	32	0
Amortization of loan discount, issuance costs and other	9	10
Amortization of premium associated with troubled debt restructuring	(41)	(42)
Interest expense on revolving credit facilities	9	5
(Gains) losses on undesignated interest rate derivatives	1	0
Capitalized interest	(51)	(68)
Total interest expense	$ 95	$ 62