Long-Term Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Commercial paper	$ 500
Revolving credit facilities	1,250
Total debt	47,226	40,458
Less: current portion	2,177	2,376
Long-term debt	45,049	38,082
Weighted average interest rate	4.89%
Credit facility interest rate	1.28%
Commercial Paper Program
Weighted average interest rate	0.336%
Senior notes with maturities of 5 years or less [Member]
Senior notes	15,787	12,991
Weighted average interest rate	4.802%
Senior notes with maturities between 6 and 10 years [Member]
Senior notes	11,534	10,334
Weighted average interest rate	4.558%
Senior notes with maturities greater than 10 years [Member]
Senior notes	17,922	16,801
Weighted average interest rate	6.00%
Other Including Capital Lease Obligations [Member]
Other, including capital lease obligations	$ 233	$ 332

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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