Investments in Securities Other-than-temporary Impairments 1 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]
OTTI recognized in Investment gains, net	$ 170	$ 51
Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	6,284
Weighted average collateral default	45.50%
Weighted average collateral severities	61.10%
Weighted average voluntary prepayment rates	2.50%
Average credit enhancement	15.90%
Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	866
Weighted average collateral default	31.70%
Weighted average collateral severities	46.40%
Weighted average voluntary prepayment rates	7.60%
Average credit enhancement	3.90%
Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	1,810
Weighted average collateral default	14.60%
Weighted average collateral severities	47.80%
Weighted average voluntary prepayment rates	11.00%
Average credit enhancement	5.00%
Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	899
Weighted average collateral default	22.80%
Weighted average collateral severities	40.10%
Weighted average voluntary prepayment rates	8.10%
Average credit enhancement	8.30%
Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	1,590
Weighted average collateral default	12.00%
Weighted average collateral severities	37.90%
Weighted average voluntary prepayment rates	11.80%
Average credit enhancement	3.80%
2004 and Prior [Member] | Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	105
Weighted average collateral default	25.90%
Weighted average collateral severities	54.70%
Weighted average voluntary prepayment rates	8.00%
Average credit enhancement	38.80%
2004 and Prior [Member] | Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	108
Weighted average collateral default	24.90%
Weighted average collateral severities	55.00%
Weighted average voluntary prepayment rates	9.60%
Average credit enhancement	3.60%
2004 and Prior [Member] | Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	758
Weighted average collateral default	8.10%
Weighted average collateral severities	44.30%
Weighted average voluntary prepayment rates	13.40%
Average credit enhancement	11.30%
2004 and Prior [Member] | Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	115
Weighted average collateral default	16.50%
Weighted average collateral severities	38.00%
Weighted average voluntary prepayment rates	9.40%
Average credit enhancement	24.30%
2004 and Prior [Member] | Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	296
Weighted average collateral default	11.00%
Weighted average collateral severities	33.70%
Weighted average voluntary prepayment rates	11.00%
Average credit enhancement	10.10%
2005 [Member] | Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	7
Weighted average collateral default	44.00%
Weighted average collateral severities	65.00%
Weighted average voluntary prepayment rates	3.90%
Average credit enhancement	59.50%
2005 [Member] | Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	440
Weighted average collateral default	30.00%
Weighted average collateral severities	54.20%
Weighted average voluntary prepayment rates	7.70%
Average credit enhancement	6.80%
2005 [Member] | Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	689
Weighted average collateral default	17.90%
Weighted average collateral severities	46.00%
Weighted average voluntary prepayment rates	10.00%
Average credit enhancement	0.70%
2005 [Member] | Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	131
Weighted average collateral default	26.20%
Weighted average collateral severities	54.10%
Weighted average voluntary prepayment rates	8.50%
Average credit enhancement	28.10%
2005 [Member] | Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	508
Weighted average collateral default	15.50%
Weighted average collateral severities	39.20%
Weighted average voluntary prepayment rates	10.00%
Average credit enhancement	6.10%
2006 [Member] | Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	5,850
Weighted average collateral default	46.00%
Weighted average collateral severities	63.30%
Weighted average voluntary prepayment rates	2.40%
Average credit enhancement	15.30%
2006 [Member] | Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	318
Weighted average collateral default	36.30%
Weighted average collateral severities	35.50%
Weighted average voluntary prepayment rates	6.80%
Average credit enhancement	0.00%
2006 [Member] | Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	363
Weighted average collateral default	21.90%
Weighted average collateral severities	53.20%
Weighted average voluntary prepayment rates	8.30%
Average credit enhancement	0.10%
2006 [Member] | Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	653
Weighted average collateral default	23.30%
Weighted average collateral severities	37.20%
Weighted average voluntary prepayment rates	7.90%
Average credit enhancement	1.50%
2006 [Member] | Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	786
Weighted average collateral default	10.10%
Weighted average collateral severities	38.40%
Weighted average voluntary prepayment rates	13.20%
Average credit enhancement	0.00%
2007 and After [Member] | Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	322
Weighted average collateral default	43.20%
Weighted average collateral severities	20.70%
Weighted average voluntary prepayment rates	1.40%
Average credit enhancement	19.60%
2007 and After [Member] | Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	0
2007 and After [Member] | Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	0
2007 and After [Member] | Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	0
2007 and After [Member] | Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 0