Condensed Financial Information (Parent Company) (Long-term Debt Outstanding) (Details) (Parent Company [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Long-term Debt [Abstract]
Senior notes	$ 15,317us-gaap_SeniorNotes	$ 15,938us-gaap_SeniorNotes
Notes Payable, Related Parties	3,600	3,600
Long-term Debt	18,917us-gaap_LongTermDebt	19,538us-gaap_LongTermDebt
Senior Notes, Unaffiliated [Member]
Long-term Debt [Abstract]
Interest Rate Range Minimum	1.76%
Interest Rate Range Maximum	7.72%
Weighted Average Interest Rate	5.23%
Debt Instrument, Maturity Date Range, Start	Jun. 15, 2015
Debt Instrument, Maturity Date Range, End	Dec. 15, 2044
Senior notes	15,317	15,938
Senior Notes, Affiliated [Member]
Long-term Debt [Abstract]
Interest Rate Range Minimum	3.54%
Interest Rate Range Maximum	7.44%
Weighted Average Interest Rate	5.16%
Debt Instrument, Maturity Date Range, Start	Sep. 30, 2016
Debt Instrument, Maturity Date Range, End	Dec. 31, 2033
Senior notes	500
Notes Payable, Related Parties	3,100	3,100
Other Affiliated Debt [Member]
Long-term Debt [Abstract]
Interest Rate Range Minimum	0.93%
Interest Rate Range Maximum	0.95%
Weighted Average Interest Rate	0.94%
Debt Instrument, Maturity Date Range, Start	Dec. 30, 2015
Debt Instrument, Maturity Date Range, End	Mar. 31, 2016
Notes Payable, Related Parties	$ 500	$ 500

When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Subparagraph (SX 210.5-02.22(a)(1))

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

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Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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-Name Regulation S-X (SX)

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Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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Weighted average interest rate of debt outstanding.

+ References

No definition available.

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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- Definition

The amount for notes payable (written promise to pay), due to related parties.

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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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