Investments and Derivative Instruments Level 4 Cash Flow Hedges (Details) - USD ($)	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 56,000,000
Maximum Term Over for Hedging Exposure to Variability of Future Cash Flows	2 years
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 107,000,000	$ 49,000,000
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	24,000,000	7,000,000
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	106,000,000	56,000,000
Currency Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	1,000,000	(7,000,000)
Gain (Loss) on Investments [Member] \| Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	5,000,000
Gain (Loss) on Investments [Member] \| Currency Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	4,000,000
Investment Income [Member] \| Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	15,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Investments [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	5,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Investments [Member] \| Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		1,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Investments [Member] \| Currency Swap [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	4,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Gain (Loss) on Investments [Member] \| Currency Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(10,000,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Investment Income [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	15,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Investment Income [Member] \| Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		16,000,000
Accumulated Other Comprehensive Income (Loss) [Member]
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Loss on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring	$ 0	$ 0

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)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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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
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624177-113959

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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=56946850&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1),(2)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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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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No definition available.

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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
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ 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 (d)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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