Investments and Derivative Instruments Level 4 Cash Flow Hedges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Derivatives in Cash Flow Hedging Relationships [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 44
Maximum Term Over for Hedging Exposure to Variability of Future Cash Flows	3 years
Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	49	43
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	(1)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7	24
Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	56	44
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net		(1)
Currency Swap [Member] \| Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(7)	(1)
Gain (Loss) on Investments [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1
Gain (Loss) on Investments [Member] \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(10)
Investment Income [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	16
Accumulated Other Comprehensive Income (Loss) [Member]
Derivatives in Cash Flow Hedging Relationships [Abstract]
Loss on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring		$ 0

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Maximum term over for hedging exposure to variability of future cash flows.

+ References

No definition available.

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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

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-Section 50

-Paragraph 4C

-Subparagraph (d)

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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- Definition

The amount of loss reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

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