Fair Value Measurements (Changes in Level 3 Instruments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	$ 2,816	$ 3,146
Cash Accruals Not Included In Schedule Assets Measured For Fair Value On Recurring Basis	9	2
Domestic Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	2,953	3,591	3,235
Net realized/unrealized gains (losses) included in earnings	(497)	66
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	135	32
Purchases	380	483
Sales	(424)	(214)
Settlements	(231)	(110)
Transfers into Level 3	108	299
Transfers out of Level 3	(109)	(200)
Net change in unrealized gains (losses) relating to instruments still held	0	0
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	96	77	77
Net realized/unrealized gains (losses) included in earnings	0	0
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	(7)	10
Purchases	21	16
Sales	0	0
Settlements	(5)	(1)
Transfers into Level 3	10	78
Transfers out of Level 3	0	(103)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Residential Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	86	100	41
Net realized/unrealized gains (losses) included in earnings	0	(3)
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	(5)	1
Purchases	0	6
Sales	(2)	0
Settlements	(7)	(3)
Transfers into Level 3	0	135
Transfers out of Level 3	0	(77)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	10	6	4
Net realized/unrealized gains (losses) included in earnings	0	0
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	0	(1)
Purchases	0	0
Sales	0	0
Settlements	(6)	0
Transfers into Level 3	10	6
Transfers out of Level 3	0	(3)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	6,898	5,023	4,040
Net realized/unrealized gains (losses) included in earnings	5	1
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	32	(25)
Purchases	2,632	1,490
Sales	(4)	(502)
Settlements	(795)	0
Transfers into Level 3	12	25
Transfers out of Level 3	(7)	(6)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Foreign Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	1,064	1,218	1,204
Net realized/unrealized gains (losses) included in earnings	(103)	(11)
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	49	19
Purchases	5,814	341
Sales	(3)	(51)
Settlements	(5,874)	(172)
Transfers into Level 3	21	24
Transfers out of Level 3	(58)	(136)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Foreign Government Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	31	42	84
Net realized/unrealized gains (losses) included in earnings	1	(33)
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	(12)	38
Purchases	0	65
Sales	0	(72)
Settlements	0	(40)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Net change in unrealized gains (losses) relating to instruments still held	0	0
US Treasury and Government [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	225	277	253
Net realized/unrealized gains (losses) included in earnings	0	0
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	(52)	24
Purchases	0	0
Sales	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Net change in unrealized gains (losses) relating to instruments still held	0	0
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	72	83	35
Net realized/unrealized gains (losses) included in earnings	3	(1)
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	1	(3)
Purchases	6	16
Sales	0	(6)
Settlements	(21)	(12)
Transfers into Level 3	0	54
Transfers out of Level 3	0	0
Net change in unrealized gains (losses) relating to instruments still held	0	0
Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	11	13	17
Net realized/unrealized gains (losses) included in earnings	0	0
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	0	(1)
Purchases	0	3
Sales	0	(3)
Settlements	0	(1)
Transfers into Level 3	0	2
Transfers out of Level 3	(2)	(4)
Net change in unrealized gains (losses) relating to instruments still held	0	0
Trading [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	0	0	0
Net realized/unrealized gains (losses) included in earnings	0	0
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Net change in unrealized gains (losses) relating to instruments still held	0	0
Derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	164	416	369
Net realized/unrealized gains (losses) included in earnings	(66)	29
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	2	(1)
Purchases	(2)	(1)
Sales	0	0
Settlements	(226)	(112)
Transfers into Level 3	37	190
Transfers out of Level 3	3	(58)
Net change in unrealized gains (losses) relating to instruments still held	30	(160)
Other 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	494	799	817
Net realized/unrealized gains (losses) included in earnings	(68)	50
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	12	2
Purchases	538	159
Sales	(779)	(137)
Settlements	0	0
Transfers into Level 3	4	0
Transfers out of Level 3	(12)	(92)
Net change in unrealized gains (losses) relating to instruments still held	102	(43)
Total [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	12,104	11,645	10,176
Net realized/unrealized gains (losses) included in earnings	(725)	98
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	155	95
Purchases	9,389	2,578
Sales	(1,212)	(985)
Settlements	(7,165)	(451)
Transfers into Level 3	202	813
Transfers out of Level 3	(185)	(679)
Net change in unrealized gains (losses) relating to instruments still held	$ 132	$ (203)