Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ (64)
Maximum length of time hedged in interest rate cash flow hedges	June 2031
Maximum length of time hedged in foreign currency cash flow hedges	September 2030
Margin Cash Collateral Not Netted Against Derivative Assets	24	30
Margin Cash Collateral Not Netted Against Derivative Liabilities	$ 42	$ 49