Derivatives (Primary Risks) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Notional Amount	$ 406,021	$ 404,895
Estimated Fair Value Assets	10,171	8,595
Estimated Fair Value Liabilities	5,166	6,521
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	40,872	38,634
Estimated Fair Value Assets	2,934	2,425
Estimated Fair Value Liabilities	697	1,145
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	10,347	12,067
Estimated Fair Value Assets	1,853	1,534
Estimated Fair Value Liabilities	114	290
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,215	6,419
Estimated Fair Value Assets	1,737	1,282
Estimated Fair Value Liabilities	24	78
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,772	2,713
Estimated Fair Value Assets	116	252
Estimated Fair Value Liabilities	42	135
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,360	2,935
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	48	77
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	20,706	16,023
Estimated Fair Value Assets	813	491
Estimated Fair Value Liabilities	582	808
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,733	3,121
Estimated Fair Value Assets	320	83
Estimated Fair Value Liabilities	4	141
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	280	450
Estimated Fair Value Assets	49	7
Estimated Fair Value Liabilities	0	7
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Foreign currency swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	17,693	12,452
Estimated Fair Value Assets	444	401
Estimated Fair Value Liabilities	578	660
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	9,819	10,544
Estimated Fair Value Assets	268	400
Estimated Fair Value Liabilities	1	47
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,250	3,182
Estimated Fair Value Assets	147	82
Estimated Fair Value Liabilities	0	47
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Currency options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,569	7,362
Estimated Fair Value Assets	121	318
Estimated Fair Value Liabilities	1	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	365,149	366,261
Estimated Fair Value Assets	7,237	6,170
Estimated Fair Value Liabilities	4,469	5,376
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	94,771	107,354
Estimated Fair Value Assets	3,535	3,330
Estimated Fair Value Liabilities	1,538	1,767
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate floors [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	62,645	63,064
Estimated Fair Value Assets	391	451
Estimated Fair Value Liabilities	214	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	116	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	5,503	6,011
Estimated Fair Value Assets	4	9
Estimated Fair Value Liabilities	5	9
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	44,701	40,978
Estimated Fair Value Assets	671	255
Estimated Fair Value Liabilities	132	243
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Synthetic GICs [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	4,315	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	10,844	9,307
Estimated Fair Value Assets	281	133
Estimated Fair Value Liabilities	432	684
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Foreign currency forwards [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	13,802	11,311
Estimated Fair Value Assets	134	69
Estimated Fair Value Liabilities	272	359
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency futures [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	455	1,316
Estimated Fair Value Assets	0	1
Estimated Fair Value Liabilities	2	1
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	8,136	2,265
Estimated Fair Value Assets	301	53
Estimated Fair Value Liabilities	110	48
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps - purchased [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,773	3,725
Estimated Fair Value Assets	9	7
Estimated Fair Value Liabilities	33	51
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps - written [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	10,929	9,055
Estimated Fair Value Assets	154	166
Estimated Fair Value Liabilities	7	1
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity futures [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,010	5,157
Estimated Fair Value Assets	24	1
Estimated Fair Value Liabilities	5	43
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity Options [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	37,892	37,411
Estimated Fair Value Assets	1,349	1,344
Estimated Fair Value Liabilities	1,063	1,068
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Variance swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	22,272	21,636
Estimated Fair Value Assets	195	174
Estimated Fair Value Liabilities	643	577
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Total rate of return swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	3,496	3,802
Estimated Fair Value Assets	73	0
Estimated Fair Value Liabilities	$ 13	$ 179