Derivative Instruments (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flow hedges [Member] | Interest Rate Contract [Member]
Summary of effective portion of the gains (losses) recognized in other comprehensive income and the gains (losses) reclassified from other comprehensive income (Loss) into earnings
Gains (Losses) Recognized in Other Comprehensive Income (Loss)	$ 1	$ 5
Gains (Losses) Reclassified from Other Comprehensive Income (Loss) into Earnings	(33)	(34)
Net investment hedges [Member] | Foreign exchange forward contracts [Member]
Summary of effective portion of the gains (losses) recognized in other comprehensive income and the gains (losses) reclassified from other comprehensive income (Loss) into earnings
Gains (Losses) Recognized in Other Comprehensive Income (Loss)	(6)	(32)
Gains (Losses) Reclassified from Other Comprehensive Income (Loss) into Earnings
Net investment hedges [Member] | Non-derivative debt instruments [Member]
Summary of effective portion of the gains (losses) recognized in other comprehensive income and the gains (losses) reclassified from other comprehensive income (Loss) into earnings
Gains (Losses) Recognized in Other Comprehensive Income (Loss)
Gains (Losses) Reclassified from Other Comprehensive Income (Loss) into Earnings