Fair Value Measurements (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investment securities	$ 45,340	$ 43,938
Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	19,415	19,374
Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,097	3,199
Domestic Corporate Debt Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Domestic Corporate Debt Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	22,512	22,573
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,843	2,875
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	7	49
Commercial Mortgage Backed Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Commercial Mortgage Backed Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,850	2,924
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,849	2,499
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	209	225
US States and Political Subdivisions Debt Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
US States and Political Subdivisions Debt Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,058	2,724
Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	76	89
Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	1,239	1,292
Foreign Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	1,537	1,486
Foreign Corporate Debt Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Foreign Corporate Debt Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,852	2,867
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	609	690
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,132	2,540
Asset-backed Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Asset-backed Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,741	3,230
Foreign Government Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	804	777
Foreign Government Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	1,618	1,333
Foreign Government Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	274	156
Foreign Government Debt Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Foreign Government Debt Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,696	2,266
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,112	3,158
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	224	210
US Treasury and Government [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
US Treasury and Government [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	3,336	3,368
Retained Interest [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Retained Interest [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Retained Interest [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	45	39
Retained Interest [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Retained Interest [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	45	39
Available-for-sale Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	1,047	677
Available-for-sale Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	18	20
Available-for-sale Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	22	24
Available-for-sale Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Available-for-sale Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	1,087	721
Trading [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	475	417
Trading [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Trading [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Trading [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Trading [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	475	417
Derivatives [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivatives	0	0
Derivatives [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivative Assets	0	0
Derivatives [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivatives	5,896	6,553
Derivatives [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivative Assets	10,457	10,997
Derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivatives	43	103
Derivatives [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivative Assets	333	359
Derivatives [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivatives	(3,573)	(3,857)
Derivatives [Member] | Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivative Assets	(3,583)	(3,867)
Derivatives [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivatives	2,366	2,799
Derivatives [Member] | Net Balance [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Derivative Assets	7,207	7,489
Other [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Other	0	0
Other	0	0
Other [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Other	0	0
Other	908	920
Other [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Other	1,149	906
Other	0	0
Other [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Other	0	0
Other	0	0
Other [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Other	1,149	906
Other	908	920
Total [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total	2,402	2,007
Total	0	0
Total [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total	44,803	44,934
Total	6,804	7,473
Total [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total	10,074	9,259
Total	43	103
Total [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total	(3,583)	(3,867)
Total	(3,573)	(3,857)
Total [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total	53,696	52,333
Total	3,274	3,719
GIC [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	4,927	5,706
Obligations To Annuitants And Policyholders [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	27,958	27,141
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	47
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,643	2,696
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	45	66
Residential Mortgage Backed Securities [Member] | Netting Adjustment [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	0	0
Residential Mortgage Backed Securities [Member] | Net Balance [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	2,688	2,809
Non Binding Broker Quotes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Investments, Fair Value Disclosure	$ 1,038	$ 1,054