Derivative and Hedging Activities - Components of Interest Income and Interest Expense Table (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest expense on senior notes	$ 171	$ 170	$ 513	$ 534
Interest expense on term loan	0	0	0	36
Amortization of loan discount, issuance costs and other	14	9	37	44
Interest expense on credit facilities	2	6	8	22
Gains on terminated fair value hedges	0	0	(2)	(2)
(Gains) losses on undesignated interest rate derivatives	0	2	(10)	(48)
Capitalized interest	(99)	(170)	(336)	(504)
Total interest expense	$ 88	$ 17	$ 210	$ 82