Derivatives (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Interest rate [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2010 Interest rate [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2011 Interest rate [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2010 Interest rate [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2011 Long-Term Debt [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2010 Long-Term Debt [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2011 Long-Term Debt [Member] Net Interest and other Financing Costs [Member]	Sep. 30, 2010 Long-Term Debt [Member] Net Interest and other Financing Costs [Member]
Foreign Currency Derivative [Line Items]
Notional amount of foreign currency derivatives		$ 0
Pretax unrealized gain (loss) on interest rate derivatives in OCI	10
Interest Rate Derivative [Line Items]
Notional amount of interest rate derivatives		500	1,450
Weighted-average, LIBOR-based, floating rate		3.65%
Interest rate swaps	29
Derivative (Fair Value Hedges):
Change in unrealized gain (loss) on fair value hedging instruments				26	15	25	39
Hedged Item (Fair Value Hedges):
Change in unrealized gain (loss) on hedged item in fair value hedge								$ (26)	$ (15)	$ (25)	$ (39)