Derivatives (Primary Risks) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Notional Amount	$ 401,592	$ 404,895
Estimated Fair Value Assets	9,252	8,595
Estimated Fair Value Liabilities	5,582	6,521
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	38,401	38,634
Estimated Fair Value Assets	2,694	2,425
Estimated Fair Value Liabilities	791	1,145
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	10,818	12,067
Estimated Fair Value Assets	1,886	1,534
Estimated Fair Value Liabilities	65	290
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,213	6,419
Estimated Fair Value Assets	1,653	1,282
Estimated Fair Value Liabilities	30	78
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,780	2,713
Estimated Fair Value Assets	229	252
Estimated Fair Value Liabilities	31	135
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,825	2,935
Estimated Fair Value Assets	4	0
Estimated Fair Value Liabilities	4	77
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	18,439	16,023
Estimated Fair Value Assets	768	491
Estimated Fair Value Liabilities	639	808
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,878	3,121
Estimated Fair Value Assets	266	83
Estimated Fair Value Liabilities	17	141
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	640	450
Estimated Fair Value Assets	45	7
Estimated Fair Value Liabilities	8	7
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Foreign currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	14,921	12,452
Estimated Fair Value Assets	457	401
Estimated Fair Value Liabilities	614	660
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	9,144	10,544
Estimated Fair Value Assets	40	400
Estimated Fair Value Liabilities	87	47
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,725	3,182
Estimated Fair Value Assets	1	82
Estimated Fair Value Liabilities	19	47
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Currency options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,419	7,362
Estimated Fair Value Assets	39	318
Estimated Fair Value Liabilities	68	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	363,191	366,261
Estimated Fair Value Assets	6,558	6,170
Estimated Fair Value Liabilities	4,791	5,376
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	95,551	107,354
Estimated Fair Value Assets	3,405	3,330
Estimated Fair Value Liabilities	1,388	1,767
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate floors [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	67,265	63,064
Estimated Fair Value Assets	457	451
Estimated Fair Value Liabilities	285	346
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate caps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	36,605	39,460
Estimated Fair Value Assets	111	177
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate futures [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,364	6,011
Estimated Fair Value Assets	3	9
Estimated Fair Value Liabilities	6	9
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	39,361	40,978
Estimated Fair Value Assets	524	255
Estimated Fair Value Liabilities	179	243
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Synthetic GICs [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	4,362	4,409
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Foreign currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	9,222	9,307
Estimated Fair Value Assets	124	133
Estimated Fair Value Liabilities	712	684
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	12,669	11,311
Estimated Fair Value Assets	107	69
Estimated Fair Value Liabilities	95	359
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency futures [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	382	1,316
Estimated Fair Value Assets	1	1
Estimated Fair Value Liabilities	0	1
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	8,389	2,265
Estimated Fair Value Assets	155	53
Estimated Fair Value Liabilities	7	48
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps - purchased [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,675	3,725
Estimated Fair Value Assets	6	7
Estimated Fair Value Liabilities	49	51
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps - written [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	9,982	9,055
Estimated Fair Value Assets	175	166
Estimated Fair Value Liabilities	2	1
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity futures [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,814	5,157
Estimated Fair Value Assets	1	1
Estimated Fair Value Liabilities	11	43
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity Options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	38,116	37,411
Estimated Fair Value Assets	1,272	1,344
Estimated Fair Value Liabilities	1,228	1,068
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Variance swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	21,985	21,636
Estimated Fair Value Assets	217	174
Estimated Fair Value Liabilities	691	577
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Total rate of return swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,449	3,802
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	$ 138	$ 179