Commercial Paper and Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Number Of Years Of Revolving Bank Credit	5 years
Maximum percentage of indebtedness to total net capital bank covenant	50.00%
Revolving Credit Facility [Member]
Five-year revolving bank credit facility, which matures in May 2012	3,000,000,000
Number of banks that comprise revolving bank credit facility (banks)	21
Termination Of Interest Rate Swap Fair Value Hedges [Member]
Notional Amount of Interest Rate Fair Value Hedge Derivatives	5,400,000,000
Derivative, Gain on Derivative	132,000,000
Weighted-average period gain amortization	4.1
Minimum [Member] | Revolving Credit Facility [Member]
Debt instrument interest rate during period	1.20%
Maximum [Member] | Revolving Credit Facility [Member]
Debt instrument interest rate during period	1.70%