Derivatives and Hedging Activities Interest Income and Interest Expense Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure Interest Income And Interest Expense [Abstract]
Interest Expense on Senior Notes	$ 732	$ 653	$ 718
Interest Expense on Credit Facilities	70	70	61
Interest Expense on Term Loans	173	0	0
(Gains) losses on interest rate derivatives	(7)	14	(80)
Amortization of Financing Costs and Discounts	89	39	36
Capitalized Interest	(980)	(732)	(716)
Interest Expense	$ 77	$ 44	$ 19