Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Loss
Unrealized net gains (losses) on hedges arising during the period, Before Tax Amount	$ 70	$ 3	$ 78	$ 9
Less: Reclassification adjustment for net (gains) losses on hedges included in interest income for loans and interest expense on long-term debt, Before Tax Amount	(29)	(7)	(52)	(14)
Net change, Before Tax Amount	41	(4)	26	(5)
Unrealized holding gains (losses) arising during the period on securities available for sale, Before Tax Amount	156	(503)	272	(503)
Reclassification adjustment for net (gains) losses on securities available for sale included in securities gains, net, Before Tax Amount	(1)	(27)	(3)	(123)
Less: accretion of fair value adjustment on securities available for sale, Before Tax Amount	(18)	(23)	(24)	(38)
Less: accretion of fair value adjustment on held to maturity securities, Before Tax Amount		(3)		(11)
Less: amortization of net unrealized (gains) losses on held to maturity securities, Before Tax Amount	5	11	10	25
Net change, Before Tax Amount	142	(545)	255	(650)
Foreign currency translation adjustment, Before Tax Amount	4	(3)		(5)
Pension and other benefits arising during the period, Before Tax Amount	(4)		(4)
Amortization of prior service costs, Before Tax Amount	(4)		(4)
Recognized net actuarial (gain) loss, Before Tax Amount	15	29	29	58
Net change, Before Tax Amount	7	29	21	58
Net change in accumulated other comprehensive loss, Before Tax Amount	194	(523)	302	(602)
Unrealized net gains (losses) on hedges arising during the period, Tax Effect	(28)	(1)	(31)	(3)
Less: Reclassification adjustment for net (gains) losses on hedges included in interest income for loans and interest expense on long-term debt, Tax Effect	12	2	21	5
Net change, Tax Effect	(16)	1	(10)	2
Unrealized holding gains (losses) arising during the period on securities available for sale, Tax Effect	(61)	197	(107)	197
Reclassification adjustment for net (gains) losses on securities available for sale included in securities gains, net, Tax Effect		11	1	49
Less: accretion of fair value adjustment on securities available for sale, Tax Effect	8	10	10	16
Less: accretion of fair value adjustment on held to maturity securities, Tax Effect		1		4
Less: amortization of net unrealized (gains) losses on held to maturity securities, Tax Effect	(2)	(4)	(4)	(10)
Net change, Tax Effect	(55)	215	(100)	256
Foreign currency translation adjustment, Tax Effect	(2)	1		2
Pension and other benefits arising during the period, Tax Effect	2		2
Amortization of prior service costs, Tax Effect	2		2
Recognized net actuarial (gain) loss, Tax Effect	(7)	(12)	(13)	(23)
Net change, Tax Effect	(3)	(12)	(9)	(23)
Net change in accumulated other comprehensive loss, Tax Effect	(76)	205	(119)	237
Unrealized net gains (losses) on hedges arising during the period, Net of Tax	42	2	47	6
Less: Reclassification adjustment for net (gains) losses on hedges included in interest income for loans and interest expense on long-term debt, Net of Tax	(17)	(5)	(31)	(9)
Net change, Net of Tax	25	(3)	16	(3)
Unrealized holding gains (losses) arising during the period on securities available for sale, Net of Tax	95	(306)	165	(306)
Reclassification adjustment for net (gains) losses on securities available for sale included in securities gains, net, Net of Tax	(1)	(16)	(2)	(74)
Less: accretion of fair value adjustment on securities available for sale, Net of Tax	(10)	(13)	(14)	(22)
Less: accretion of fair value adjustment on held to maturity securities, Net of Tax		(2)		(7)
Less: amortization of net unrealized (gains) losses on held to maturity securities, Net of Tax	3	7	6	15
Net change, Net of Tax	87	(330)	155	(394)
Foreign currency translation adjustment, Net of Tax	2	(2)		(3)
Pension and other benefits arising during the period, Net of Tax	(2)		(2)
Amortization of prior service costs, Net of Tax	(2)		(2)
Recognized net actuarial (gain) loss, Net of Tax	8	17	16	35
Net change, Net of Tax	4	17	12	35
Net change in accumulated other comprehensive loss, Net of Tax	$ 118	$ (318)	$ 183	$ (365)