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	$ 2,813	$ 2,990
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	2,918	3,552	3,235
Net realized/unrealized gains (losses) included in earnings	(477)	66
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	122	32
Purchases	376	444
Sales	(423)	(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	1,052	1,212	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	335
Sales	(3)	(51)
Settlements	(5,874)	(172)
Transfers into Level 3	15	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	163	262	141
Net realized/unrealized gains (losses) included in earnings	(78)	(11)
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	2	(1)
Purchases	(1)	(2)
Sales	0	0
Settlements	(53)	(39)
Transfers into Level 3	33	178
Transfers out of Level 3	(2)	(4)
Net change in unrealized gains (losses) relating to instruments still held	(31)	160
Other 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	293	432	388
Net realized/unrealized gains (losses) included in earnings	(94)	2
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	12	2
Purchases	493	152
Sales	(542)	(70)
Settlements	0	0
Transfers into Level 3	4	0
Transfers out of Level 3	(12)	(42)
Net change in unrealized gains (losses) relating to instruments still held	(90)	(1)
Total [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in Level 3	11,855	11,079	9,519
Net realized/unrealized gains (losses) included in earnings	(743)	10
Net realized/unrealized gains (losses) included in accumulated other comprehensive income	142	95
Purchases	9,341	2,525
Sales	(974)	(918)
Settlements	(6,992)	(378)
Transfers into Level 3	192	801
Transfers out of Level 3	(190)	(575)
Net change in unrealized gains (losses) relating to instruments still held	$ (121)	$ 159