Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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-Name Accounting Standards Codification

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-SubTopic 30

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Contractual interest rate for funds borrowed, under the debt agreement.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Total debt and equity financial instruments including: (1) securities held-to-maturity and (2) securities available-for-sale that will be held for the long-term.

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Fair Value of Financial Instruments #2 (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Feb. 28, 2015	Mar. 31, 2015	Dec. 31, 2014
Investments in Marketable Securities [Abstract]
Marketable Securities, Noncurrent		$ 331us-gaap_MarketableSecuritiesNoncurrent	$ 336us-gaap_MarketableSecuritiesNoncurrent
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, Notional Amount		140invest_DerivativeNotionalAmount	146invest_DerivativeNotionalAmount
Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Face Amount	600
Thirty Year Term [Member] \| Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.85%
Thirty Year Term [Member] \| April 45 Maturity [Domain] \| Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Maturity Date	Apr. 15, 2045
Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, Notional Amount		$ 24	$ 34