Debt and Financing Costs (Details) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Carrying amounts and estimated fair values of the Company's debt
Carrying Amount, Money market lines of credit	$ 48		$ 48		$ 46
Carrying Amount, Commercial paper	620		620		913
Carrying Amount	7,852		7,852		8,141
Fair Value	8,486		8,486		8,829
Financing Costs, Net
Interest expense	109	75	217	151
Amortization of deferred loan costs	1	1	3	3
Capitalized interest	(63)	(18)	(124)	(35)
Interest income	(6)	(2)	(10)	(4)
Financing costs, net	41	56	86	115
Money Market Lines Of Credit [Member]
Carrying amounts and estimated fair values of the Company's debt
Fair Value	48		48		46
Commercial Paper [Member]
Carrying amounts and estimated fair values of the Company's debt
Fair Value	620		620		913
Notes And Debentures [Member]
Carrying amounts and estimated fair values of the Company's debt
Carrying Amount	7,184		7,184		7,182
Fair Value	$ 7,818		$ 7,818		$ 7,870

Total debt current and long term.

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The net increase(decrease) in interest income during the period representing the allocation of deferred loan origination fees less deferred loan origination costs using the effective interest method over the term of the debt arrangement to which they pertain taking into account the effect of prepayments.

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Carrying value as of the balance sheet date of long-term unsecured obligations issued by corporations and other borrowers to investors (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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The amount of interest that was capitalized during the period.

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