Notes Payable To Banks and Long-Term Debt (Details) (USD $)	3 Months Ended	12 Months Ended
Dec. 31, 2010	Dec. 31, 2010	Dec. 31, 2009
Long-Term Debt (Table Amounts) [Abstract]
Notes and debentures due 2011 to 2040, rates from 1.85% to 9.375%	$ 4,673,000,000	$ 4,673,000,000	$ 3,964,000,000
Capital lease obligations	41,000,000	41,000,000	35,000,000
Total long-term debt	4,714,000,000	4,714,000,000	3,999,000,000
Less current portion	774,000,000	774,000,000	91,000,000
Long-term debt, net of current portion	3,940,000,000	3,940,000,000	3,908,000,000
Long-Term Debt Maturities (Table Amounts) [Abstract]
2011	773,000,000	773,000,000
2012	5,000,000	5,000,000
2013	4,000,000	4,000,000
2014	353,000,000	353,000,000
2015	502,000,000	502,000,000
Thereafter	3,066,000,000	3,066,000,000
Total principal payments	4,703,000,000	4,703,000,000
Unamortized premium on long-term debt, net of discount	11,000,000	11,000,000
Total long-term debt	4,714,000,000	4,714,000,000	3,999,000,000
Credit Facility [Abstract]
Aggregate principal amount	2,000,000,000	2,000,000,000
Additional borrowing available	500,000,000	500,000,000
Maximum amount borrowed during the period		0	0
Balance outstanding at the end of the period	0	0	0
Debt Information, by Instrument [Line Items]
Loss on debt tender	(229,000,000)	(229,000,000)
$350 Million Note due 2014 at 3.70%
Debt Information, by Instrument [Line Items]
Face amount of debt			350,000,000
Stated interest rate			3.70%
Interest payment frequency		semi-annually
Debt issuance date		7/1/2009
Debt maturity date		Aug. 01, 2014
$500 Million Note due 2019 at 5.05%
Debt Information, by Instrument [Line Items]
Face amount of debt			500,000,000
Stated interest rate			5.05%
Interest payment frequency		semi-annually
Debt issuance date		7/1/2009
Debt maturity date		Aug. 01, 2019
$500 Million Note due 2015 at 1.85%
Debt Information, by Instrument [Line Items]
Face amount of debt	500,000,000	500,000,000
Stated interest rate	1.85%	1.85%
Interest payment frequency		semi-annually
Debt issuance date		11/1/2010
Debt maturity date		Nov. 15, 2015
$700 Million Note due 2021 at 3.50%
Debt Information, by Instrument [Line Items]
Face amount of debt	700,000,000	700,000,000
Stated interest rate	3.50%	3.50%
Interest payment frequency		semi-annually
Debt issuance date		11/1/2010
Debt maturity date		Mar. 15, 2021
$300 Million Note due 2040 at 5.05%
Debt Information, by Instrument [Line Items]
Face amount of debt	300,000,000	300,000,000
Stated interest rate	5.05%	5.05%
Interest payment frequency		semi-annually
Debt issuance date		11/1/2010
Debt maturity date		Nov. 15, 2040
$400 Million Note due 2009 at 8%
Debt Information, by Instrument [Line Items]
Face amount of debt			400,000,000
Stated interest rate			8.00%
Debt maturity date			Oct. 15, 2009
$750 Million Note due 2011 at 7.125%
Debt Information, by Instrument [Line Items]
Face amount of debt	750,000,000	750,000,000
Stated interest rate	7.125%	7.125%
Debt maturity date		Feb. 15, 2011
$1.919 Billion NGSC debt securities due 2016 to 2036, rates from 6.98% to 7.875%
Debt Information, by Instrument [Line Items]
Amount under debt tender offer	1,900,000,000	1,900,000,000
Amount debt tendered and accepted for purchase		682,000,000
Total purchase price on debt tender		919,000,000
Loss on debt tender		$ (229,000,000)
Interest rate, minimum		0.0698
Interest rate, maximum		0.07875
Notes and debentures due 2011 to 2040
Debt Information, by Instrument [Line Items]
Interest rate, minimum		0.0185
Interest rate, maximum		0.09375

Total purchase price paid to extinguish debt including principal, accrued and unpaid interest and any bank fees.

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Additional borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Obligation related to long-term debt (excluding convertible debt) and capital leases. Includes the amounts due both within one year and more than one year after the balance sheet date.

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Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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Interest rate stated in the contractual debt agreement.

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When presenting a range of interest rates, the lowest stated (contractual) rate for funds borrowed under the debt agreement as of the balance sheet date.

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Date when the debt instrument was issued, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

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Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

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Amount of outstanding principal due under the debt instrument at the end of the reporting period.

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The amount of debt discount (net of debt premium) that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Gross amount of debt extinguished.

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Amount represents the difference between the fair value of the payments made and the carrying amount of the debt at the time of its extinguishment.

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Amount borrowed under the credit facility as of the balance-sheet date.

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Maximum amount borrowed under the credit facility at any time during the period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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Obligation related to long-term debt (excluding convertible debt) and capital leases, the portion which is due in one year or less in the future.

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Amount of long-term debt maturities after year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.

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