Accumulated Other Comprehensive Income Level 4 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 8,278	$ 8,789	$ 8,278	$ 8,789		$ 8,162		$ 9,291
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	267	(467)	498	(344)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(34)	(18)	(23)	(28)
Other Comprehensive Income (Loss), Net of Tax	233	(485)	475	(372)
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	4	15	(103)	12
Income Tax Expense (Benefit)	30	11	11	51
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	993	790	993	790	$ 765	539	$ 1,257	1,154
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	259	(457)	468	(342)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(31)	(10)	(14)	(22)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	228	(467)	454	(364)
Gain (Loss) on Investments, Excluding Other than Temporary Impairments		16	21	34
Income before income taxes				34
Income Tax Expense (Benefit)	16	6	7	12
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	77	62	77	62	73	57	80	70
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	7	(10)	29	(2)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(3)	(8)	(9)	(6)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	4	(18)	20	(8)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(2)	(3)	(2)	(3)	(3)	(3)	(3)	(3)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1	0	1	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	1	0	1	0
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,068	849	1,068	849	$ 835	$ 593	$ 1,334	$ 1,221
Other Comprehensive Income (Loss), Net of Tax				(372)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	34	18	23	28
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	31	10	14	22
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	47	16	21	34
Income before income taxes	47	16	21
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income Tax Expense (Benefit)	2	4	5	3
Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	5		14	9
Cash Flow Hedging [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3	8	9	6
Income before income taxes	5	$ 12	14	9
Interest Rate Swap [Member] | Interest Income [Member] | Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7		12
Interest Rate Swap [Member] | Interest Income [Member] | Cash Flow Hedging [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7		12	17
Interest Rate Swap [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Cash Flow Hedging [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0
Interest Rate Swap [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0		0
Interest Rate Swap [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Cash Flow Hedging [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0			(1)
Currency Swap [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(2)		2
Currency Swap [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Cash Flow Hedging [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (2)		$ 2	$ (7)