Investments (Continuous Gross Unrealized Losses for Fixed Maturity and Equity Securities Available-For-Sale) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
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	3,290	4,480
Total number of securities in an unrealized loss position equal to or greater than 12 months	1,415	1,571
Fixed maturity securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	$ 45,873	$ 64,516
Less than 12 Months Gross Unrealized Loss	1,735	3,372
Equal to or Greater than 12 Months Estimated Fair Value	12,062	12,592
Equal to or Greater than 12 Months Gross Unrealized Loss	1,033	1,220
U.S. corporate securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	9,989	13,889
Less than 12 Months Gross Unrealized Loss	349	808
Equal to or Greater than 12 Months Estimated Fair Value	4,233	3,807
Equal to or Greater than 12 Months Gross Unrealized Loss	390	421
Foreign corporate securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	5,576	9,019
Less than 12 Months Gross Unrealized Loss	211	402
Equal to or Greater than 12 Months Estimated Fair Value	2,206	2,320
Equal to or Greater than 12 Months Gross Unrealized Loss	118	163
Foreign government debt securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	3,622	5,052
Less than 12 Months Gross Unrealized Loss	237	336
Equal to or Greater than 12 Months Estimated Fair Value	1,660	1,846
Equal to or Greater than 12 Months Gross Unrealized Loss	60	51
RMBS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	10,252	10,754
Less than 12 Months Gross Unrealized Loss	280	363
Equal to or Greater than 12 Months Estimated Fair Value	1,890	2,302
Equal to or Greater than 12 Months Gross Unrealized Loss	292	333
U.S. Treasury, agency and government guaranteed securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	8,877	15,225
Less than 12 Months Gross Unrealized Loss	458	1,037
Equal to or Greater than 12 Months Estimated Fair Value	310	357
Equal to or Greater than 12 Months Gross Unrealized Loss	16	19
CMBS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	2,790	3,696
Less than 12 Months Gross Unrealized Loss	79	142
Equal to or Greater than 12 Months Estimated Fair Value	644	631
Equal to or Greater than 12 Months Gross Unrealized Loss	19	28
ABS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	3,216	3,772
Less than 12 Months Gross Unrealized Loss	41	59
Equal to or Greater than 12 Months Estimated Fair Value	726	978
Equal to or Greater than 12 Months Gross Unrealized Loss	66	124
State and political subdivision securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	1,551	3,109
Less than 12 Months Gross Unrealized Loss	80	225
Equal to or Greater than 12 Months Estimated Fair Value	393	351
Equal to or Greater than 12 Months Gross Unrealized Loss	72	81
Equity Securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	470	445
Less than 12 Months Gross Unrealized Loss	52	69
Equal to or Greater than 12 Months Estimated Fair Value	237	207
Equal to or Greater than 12 Months Gross Unrealized Loss	50	48
Common Stock [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	81	81
Less than 12 Months Gross Unrealized Loss	8	4
Equal to or Greater than 12 Months Estimated Fair Value	65	16
Equal to or Greater than 12 Months Gross Unrealized Loss	11	1
Non-redeemable preferred stock [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	389	364
Less than 12 Months Gross Unrealized Loss	44	65
Equal to or Greater than 12 Months Estimated Fair Value	172	191
Equal to or Greater than 12 Months Gross Unrealized Loss	$ 39	$ 47