Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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Financial Instruments And Derivatives [Line Items]

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Financial Instruments And Derivatives (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial Instruments And Derivatives [Line Items]
Estimated fair value of total long-term debt, excluding capitalized lease obligations		$ 18,900	$ 11,700
Recorded book values of total long-term debt, excluding capitalized lease obligations		18,700	11,300
Derivative asset at fair value, net		21	75
Gain (loss) before-tax earnings impact of derivatives		39	110	$ (7)
Additions to long-term debt	$ 8,000	8,028	$ 5,731	$ 345
Level 1 [Member]
Financial Instruments And Derivatives [Line Items]
Estimated fair value of total long-term debt, excluding capitalized lease obligations		18,584
Level 2 [Member]
Financial Instruments And Derivatives [Line Items]
Estimated fair value of total long-term debt, excluding capitalized lease obligations		208
Level 3 [Member]
Financial Instruments And Derivatives [Line Items]
Estimated fair value of total long-term debt, excluding capitalized lease obligations		$ 62