Investments (Continuous Gross Unrealized Losses for Fixed Maturity and Equity Securities Available-For-Sale) (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Total number of securities in an unrealized loss position less than 12 months	4,916	3,153
Total number of securities in an unrealized loss position equal to or greater than 12 months	1,060	1,435
Fixed Maturity Securities
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	$ 67,046	$ 40,798
Less than 12 Months Gross Unrealized Loss	2,707	1,101
Equal to or Greater than 12 Months Estimated Fair Value	8,559	13,881
Equal to or Greater than 12 Months Gross Unrealized Loss	802	888
U.S. corporate
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	19,772	11,389
Less than 12 Months Gross Unrealized Loss	944	331
Equal to or Greater than 12 Months Estimated Fair Value	2,353	4,658
Equal to or Greater than 12 Months Gross Unrealized Loss	262	293
Foreign corporate
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	12,921	9,410
Less than 12 Months Gross Unrealized Loss	871	505
Equal to or Greater than 12 Months Estimated Fair Value	1,726	2,074
Equal to or Greater than 12 Months Gross Unrealized Loss	197	166
U.S. Treasury and agency
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	9,657	8,927
Less than 12 Months Gross Unrealized Loss	395	12
Equal to or Greater than 12 Months Estimated Fair Value	301	1,314
Equal to or Greater than 12 Months Gross Unrealized Loss	4	18
Foreign government
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	3,025	1,085
Less than 12 Months Gross Unrealized Loss	91	80
Equal to or Greater than 12 Months Estimated Fair Value	435	630
Equal to or Greater than 12 Months Gross Unrealized Loss	62	81
RMBS
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	12,298	4,180
Less than 12 Months Gross Unrealized Loss	199	92
Equal to or Greater than 12 Months Estimated Fair Value	1,767	2,534
Equal to or Greater than 12 Months Gross Unrealized Loss	190	228
State and political subdivision
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	1,752	83
Less than 12 Months Gross Unrealized Loss	78	1
Equal to or Greater than 12 Months Estimated Fair Value	101	297
Equal to or Greater than 12 Months Gross Unrealized Loss	23	25
CMBS (1)
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	2,553	1,268
Less than 12 Months Gross Unrealized Loss	61	23
Equal to or Greater than 12 Months Estimated Fair Value	413	934
Equal to or Greater than 12 Months Gross Unrealized Loss	22	22
ABS
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	5,068	4,456
Less than 12 Months Gross Unrealized Loss	68	57
Equal to or Greater than 12 Months Estimated Fair Value	1,463	1,440
Equal to or Greater than 12 Months Gross Unrealized Loss	42	55
Equity securities
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	275	178
Less than 12 Months Gross Unrealized Loss	30	30
Equal to or Greater than 12 Months Estimated Fair Value	188	193
Equal to or Greater than 12 Months Gross Unrealized Loss	43	37
Common Stock
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	191	111
Less than 12 Months Gross Unrealized Loss	27	28
Equal to or Greater than 12 Months Estimated Fair Value	3	1
Equal to or Greater than 12 Months Gross Unrealized Loss	0	0
Non-redeemable preferred stock
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	84	67
Less than 12 Months Gross Unrealized Loss	3	2
Equal to or Greater than 12 Months Estimated Fair Value	185	192
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 43	$ 37