Investments (Details 33) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	$ 39,050	$ 37,818
% of Total	100.00%	100.00%
Estimated Fair Value	40,660	38,777
% of Total	100.00%	100.00%
Greater than 1.20x [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	35,382	32,873
Greater than 1.20x [Member] | Less than 65% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	20,130	16,663
Greater than 1.20x [Member] | 65% to 75% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	9,292	9,022
Greater than 1.20x [Member] | 76% to 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	2,528	3,033
Greater than 1.20x [Member] | Greater than 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	3,432	4,155
1.00x - 1.20x [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	2,062	3,007
1.00x - 1.20x [Member] | Less than 65% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	480	125
1.00x - 1.20x [Member] | 65% to 75% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	520	765
1.00x - 1.20x [Member] | 76% to 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	131	304
1.00x - 1.20x [Member] | Greater than 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	931	1,813
Less than 1.00x [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	1,606	1,938
Less than 1.00x [Member] | Less than 65% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	432	483
Less than 1.00x [Member] | 65% to 75% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	478	513
Less than 1.00x [Member] | 76% to 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	53	135
Less than 1.00x [Member] | Greater than 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	643	807
Less than 65% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	21,042	17,271
% of Total	53.90%	45.70%
Estimated Fair Value	22,463	18,183
% of Total	55.20%	46.90%
65% to 75% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	10,290	10,300
% of Total	26.40%	27.20%
Estimated Fair Value	10,811	10,685
% of Total	26.60%	27.60%
76% to 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	2,712	3,472
% of Total	6.90%	9.20%
Estimated Fair Value	2,748	3,535
% of Total	6.80%	9.10%
Greater than 80% [Member]
Commercial Mortgage Loans - by Credit Quality Indicators with Estimated Fair Value:
Commercial mortgage loans	5,006	6,775
% of Total	12.80%	17.90%
Estimated Fair Value	$ 4,638	$ 6,374
% of Total	11.40%	16.40%