Fair Value (Recurring Fair Value Measurements) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Available-for-sale Securities, Debt Securities	$ 366,275	$ 365,425
Available-for-sale Securities, Equity Securities	3,713	3,631
Actively Traded securities	714	704
Fair Value Option And Trading Securities	16,471	16,689
Short-term investments	14,130	8,621
Mortgage loans at estimated fair value	62,409	60,118
Derivative assets	15,791	13,452
Net embedded derivatives within asset host contracts	104	160
Separate account assets	324,724	316,994
Liabilities [Abstract]
Derivative liabilities	7,822	7,022
Net embedded derivatives within liability host contracts	137	(46)
Long-term debt, at estimated fair value, relating to variable interest entities	17,714	16,286
Residential mortgage loans — FVO
Assets [Abstract]
Mortgage loans at estimated fair value	329	308
Consolidated Securitization Entities
Assets [Abstract]
Mortgage loans at estimated fair value	272	280
Liabilities [Abstract]
Long-term debt, at estimated fair value, relating to variable interest entities	143	151
Recurring [Member]
Assets [Abstract]
Available-for-sale Securities, Debt Securities	366,275	365,425
Available-for-sale Securities, Equity Securities	3,713	3,631
Actively Traded securities	714	654
Fair Value Option And Trading Securities	16,471	16,689
Short-term investments	12,652	7,663
Mortgage loans at estimated fair value	601	588
Other investments	246	264
Derivative assets	15,791	13,452
Total other invested assets	16,037	13,716
Net embedded derivatives within asset host contracts	407	377
Separate account assets	324,724	316,994
Total assets	740,880	725,083
Liabilities [Abstract]
Derivative liabilities	7,822	7,022
Net embedded derivatives within liability host contracts	137	(46)
Trading liabilities	252	239
Total liabilities	8,354	7,366
Recurring [Member] | Interest rate contracts
Assets [Abstract]
Derivative assets	10,614	9,055
Liabilities [Abstract]
Derivative liabilities	2,693	2,356
Recurring [Member] | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	3,324	2,499
Liabilities [Abstract]
Derivative liabilities	3,248	2,848
Recurring [Member] | Credit contracts
Assets [Abstract]
Derivative assets	205	189
Liabilities [Abstract]
Derivative liabilities	53	40
Recurring [Member] | Equity market contracts
Assets [Abstract]
Derivative assets	1,648	1,709
Liabilities [Abstract]
Derivative liabilities	1,828	1,778
Recurring [Member] | FVO general account securities
Assets [Abstract]
Fair Value Option And Trading Securities	651	704
Recurring [Member] | FVO contractholder-directed unit-linked investments
Assets [Abstract]
Fair Value Option And Trading Securities	15,091	15,316
Recurring [Member] | Residential mortgage loans — FVO
Assets [Abstract]
Mortgage loans at estimated fair value	329	308
Recurring [Member] | Consolidated Securitization Entities
Assets [Abstract]
Fair Value Option And Trading Securities	15	15
Mortgage loans at estimated fair value	272	280
Liabilities [Abstract]
Long-term debt, at estimated fair value, relating to variable interest entities	143	151
Recurring [Member] | U.S. corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	106,335	105,954
Recurring [Member] | Foreign corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	60,494	61,675
Recurring [Member] | Foreign government
Assets [Abstract]
Available-for-sale Securities, Debt Securities	52,361	52,666
Recurring [Member] | U.S. Treasury and agency
Assets [Abstract]
Available-for-sale Securities, Debt Securities	60,472	61,516
Recurring [Member] | RMBS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	43,784	39,846
Recurring [Member] | CMBS (1)
Assets [Abstract]
Available-for-sale Securities, Debt Securities	13,311	14,332
Recurring [Member] | ABS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	13,808	14,249
Recurring [Member] | State and political subdivision
Assets [Abstract]
Available-for-sale Securities, Debt Securities	15,710	15,187
Recurring [Member] | Common stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	2,575	2,516
Recurring [Member] | Non-redeemable preferred stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	1,138	1,115
Recurring [Member] | Level 1
Assets [Abstract]
Available-for-sale Securities, Debt Securities	36,713	36,879
Available-for-sale Securities, Equity Securities	1,598	1,558
Actively Traded securities	48	22
Fair Value Option And Trading Securities	11,595	11,638
Short-term investments	2,621	2,104
Mortgage loans at estimated fair value	0	0
Other investments	187	203
Derivative assets	44	71
Total other invested assets	231	274
Net embedded derivatives within asset host contracts	0	0
Separate account assets	86,253	83,533
Total assets	139,011	135,986
Liabilities [Abstract]
Derivative liabilities	15	11
Net embedded derivatives within liability host contracts	0	0
Trading liabilities	206	215
Total liabilities	221	226
Recurring [Member] | Level 1 | Interest rate contracts
Assets [Abstract]
Derivative assets	9	4
Liabilities [Abstract]
Derivative liabilities	6	9
Recurring [Member] | Level 1 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	1	2
Liabilities [Abstract]
Derivative liabilities	2	0
Recurring [Member] | Level 1 | Credit contracts
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring [Member] | Level 1 | Equity market contracts
Assets [Abstract]
Derivative assets	34	65
Liabilities [Abstract]
Derivative liabilities	7	2
Recurring [Member] | Level 1 | FVO general account securities
Assets [Abstract]
Fair Value Option And Trading Securities	527	552
Recurring [Member] | Level 1 | FVO contractholder-directed unit-linked investments
Assets [Abstract]
Fair Value Option And Trading Securities	11,020	11,064
Recurring [Member] | Level 1 | Residential mortgage loans — FVO
Assets [Abstract]
Mortgage loans at estimated fair value	0	0
Recurring [Member] | Level 1 | Consolidated Securitization Entities
Assets [Abstract]
Fair Value Option And Trading Securities	0	0
Mortgage loans at estimated fair value	0	0
Liabilities [Abstract]
Long-term debt, at estimated fair value, relating to variable interest entities	0	0
Recurring [Member] | Level 1 | U.S. corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | Foreign corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | Foreign government
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | U.S. Treasury and agency
Assets [Abstract]
Available-for-sale Securities, Debt Securities	34,116	36,879
Recurring [Member] | Level 1 | RMBS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	2,597	0
Recurring [Member] | Level 1 | CMBS (1)
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | ABS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | State and political subdivision
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 1 | Common stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	1,598	1,558
Recurring [Member] | Level 1 | Non-redeemable preferred stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	0	0
Recurring [Member] | Level 2
Assets [Abstract]
Available-for-sale Securities, Debt Securities	306,805	306,411
Available-for-sale Securities, Equity Securities	1,777	1,728
Actively Traded securities	656	627
Fair Value Option And Trading Securities	4,355	4,484
Short-term investments	8,673	5,223
Mortgage loans at estimated fair value	272	280
Other investments	59	61
Derivative assets	15,303	12,922
Total other invested assets	15,362	12,983
Net embedded derivatives within asset host contracts	0	0
Separate account assets	236,415	231,539
Total assets	573,659	562,648
Liabilities [Abstract]
Derivative liabilities	7,018	6,252
Net embedded derivatives within liability host contracts	8	7
Trading liabilities	46	24
Total liabilities	7,203	6,421
Recurring [Member] | Level 2 | Interest rate contracts
Assets [Abstract]
Derivative assets	10,535	8,988
Liabilities [Abstract]
Derivative liabilities	2,686	2,347
Recurring [Member] | Level 2 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	3,295	2,472
Liabilities [Abstract]
Derivative liabilities	3,151	2,755
Recurring [Member] | Level 2 | Credit contracts
Assets [Abstract]
Derivative assets	194	175
Liabilities [Abstract]
Derivative liabilities	52	38
Recurring [Member] | Level 2 | Equity market contracts
Assets [Abstract]
Derivative assets	1,279	1,287
Liabilities [Abstract]
Derivative liabilities	1,129	1,112
Recurring [Member] | Level 2 | FVO general account securities
Assets [Abstract]
Fair Value Option And Trading Securities	35	57
Recurring [Member] | Level 2 | FVO contractholder-directed unit-linked investments
Assets [Abstract]
Fair Value Option And Trading Securities	3,659	3,797
Recurring [Member] | Level 2 | Residential mortgage loans — FVO
Assets [Abstract]
Mortgage loans at estimated fair value	0	0
Recurring [Member] | Level 2 | Consolidated Securitization Entities
Assets [Abstract]
Fair Value Option And Trading Securities	5	3
Mortgage loans at estimated fair value	272	280
Liabilities [Abstract]
Long-term debt, at estimated fair value, relating to variable interest entities	131	138
Recurring [Member] | Level 2 | U.S. corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	99,014	99,012
Recurring [Member] | Level 2 | Foreign corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	54,086	55,185
Recurring [Member] | Level 2 | Foreign government
Assets [Abstract]
Available-for-sale Securities, Debt Securities	50,977	51,355
Recurring [Member] | Level 2 | U.S. Treasury and agency
Assets [Abstract]
Available-for-sale Securities, Debt Securities	26,356	24,637
Recurring [Member] | Level 2 | RMBS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	36,642	35,463
Recurring [Member] | Level 2 | CMBS (1)
Assets [Abstract]
Available-for-sale Securities, Debt Securities	12,667	13,567
Recurring [Member] | Level 2 | ABS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	11,355	12,005
Recurring [Member] | Level 2 | State and political subdivision
Assets [Abstract]
Available-for-sale Securities, Debt Securities	15,708	15,187
Recurring [Member] | Level 2 | Common stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	883	863
Recurring [Member] | Level 2 | Non-redeemable preferred stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	894	865
Recurring [Member] | Level 3
Assets [Abstract]
Available-for-sale Securities, Debt Securities	22,757	22,135
Available-for-sale Securities, Equity Securities	338	345
Actively Traded securities	10	5
Fair Value Option And Trading Securities	521	567
Short-term investments	1,358	336
Mortgage loans at estimated fair value	329	308
Other investments	0	0
Derivative assets	444	459
Total other invested assets	444	459
Net embedded derivatives within asset host contracts	407	377
Separate account assets	2,056	1,922
Total assets	28,210	26,449
Liabilities [Abstract]
Derivative liabilities	789	759
Net embedded derivatives within liability host contracts	129	(53)
Trading liabilities	0	0
Total liabilities	930	719
Recurring [Member] | Level 3 | Interest rate contracts
Assets [Abstract]
Derivative assets	70	63
Liabilities [Abstract]
Derivative liabilities	1	0
Recurring [Member] | Level 3 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	28	25
Liabilities [Abstract]
Derivative liabilities	95	93
Recurring [Member] | Level 3 | Credit contracts
Assets [Abstract]
Derivative assets	11	14
Liabilities [Abstract]
Derivative liabilities	1	2
Recurring [Member] | Level 3 | Equity market contracts
Assets [Abstract]
Derivative assets	335	357
Liabilities [Abstract]
Derivative liabilities	692	664
Recurring [Member] | Level 3 | FVO general account securities
Assets [Abstract]
Fair Value Option And Trading Securities	89	95
Recurring [Member] | Level 3 | FVO contractholder-directed unit-linked investments
Assets [Abstract]
Fair Value Option And Trading Securities	412	455
Recurring [Member] | Level 3 | Residential mortgage loans — FVO
Assets [Abstract]
Mortgage loans at estimated fair value	329	308
Recurring [Member] | Level 3 | Consolidated Securitization Entities
Assets [Abstract]
Fair Value Option And Trading Securities	10	12
Mortgage loans at estimated fair value	0	0
Liabilities [Abstract]
Long-term debt, at estimated fair value, relating to variable interest entities	12	13
Recurring [Member] | Level 3 | U.S. corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	7,321	6,942
Recurring [Member] | Level 3 | Foreign corporate
Assets [Abstract]
Available-for-sale Securities, Debt Securities	6,408	6,490
Recurring [Member] | Level 3 | Foreign government
Assets [Abstract]
Available-for-sale Securities, Debt Securities	1,384	1,311
Recurring [Member] | Level 3 | U.S. Treasury and agency
Assets [Abstract]
Available-for-sale Securities, Debt Securities	0	0
Recurring [Member] | Level 3 | RMBS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	4,545	4,383
Recurring [Member] | Level 3 | CMBS (1)
Assets [Abstract]
Available-for-sale Securities, Debt Securities	644	765
Recurring [Member] | Level 3 | ABS
Assets [Abstract]
Available-for-sale Securities, Debt Securities	2,453	2,244
Recurring [Member] | Level 3 | State and political subdivision
Assets [Abstract]
Available-for-sale Securities, Debt Securities	2	0
Recurring [Member] | Level 3 | Common stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	94	95
Recurring [Member] | Level 3 | Non-redeemable preferred stock
Assets [Abstract]
Available-for-sale Securities, Equity Securities	$ 244	$ 250