Derivative and Hedging Activities Interest Income and Interest Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest Income (Expense), Net [Abstract]
Interest Expense on Senior Notes	$ 194	$ 185	$ 380	$ 359
Interest Expense on Credit Facilities	11	16	22	37
Interest Expense on Term Loans	29	62	58	62
(Gains) losses on interest rate derivatives	50	(7)	54	(2)
Amortization of Financing Costs and Discounts	30	42	48	42
Capitalized Interest	(210)	(284)	(438)	(472)
Interest Expense	$ 104	$ 14	$ 124	$ 26