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
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 16
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	0	0
Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	13	9
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	(3)	14
Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	20	10
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	(1)
Currency Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(7)	(1)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(10)
Interest Income [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	8
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1)	1
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(10)	0
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Interest Income [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 8	$ 13

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.

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

-Topic 815

-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

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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-Publisher FASB

-Name Accounting Standards Codification

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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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The amount of net gain (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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-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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