Securities (Details 7) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	$ 995
Over One Year Through Five Years, Fair Value	1,008
Over Five Years Through Ten Years, Carrying Amount	1,258
Over Five Years Through Ten Years, Fair Value	1,313
Over Ten Years, Carrying Amount	8,088
Over Ten Years, Fair Value	8,207
Total securities held to maturity, carrying amount	10,341	$ 8,291
Total securities held to maturity, Fair Value	10,528	8,412
U.S. Treasury
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	488
Over One Year Through Five Years, Fair Value	499
Over Five Years Through Ten Years, Carrying Amount	0
Over Five Years Through Ten Years, Fair Value	0
Over Ten Years, Carrying Amount	0
Over Ten Years, Fair Value	0
Total securities held to maturity, carrying amount	488	486
Total securities held to maturity, Fair Value	499	489
U.S. government sponsored agencies
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	458
Over One Year Through Five Years, Fair Value	458
Over Five Years Through Ten Years, Carrying Amount	442
Over Five Years Through Ten Years, Fair Value	443
Over Ten Years, Carrying Amount	0
Over Ten Years, Fair Value	0
Total securities held to maturity, carrying amount	900	125
Total securities held to maturity, Fair Value	901	125
Residential mortgage-backed securities, U.S. government agency and government-sponsored agencies
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	0
Over One Year Through Five Years, Fair Value	0
Over Five Years Through Ten Years, Carrying Amount	18
Over Five Years Through Ten Years, Fair Value	18
Over Ten Years, Carrying Amount	7,252
Over Ten Years, Fair Value	7,357
Total securities held to maturity, carrying amount	7,270	5,942
Total securities held to maturity, Fair Value	7,375	6,013
U.S. government agency and government-sponsored agencies - commercial mortgage-backed securities
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	49
Over One Year Through Five Years, Fair Value	51
Over Five Years Through Ten Years, Carrying Amount	798
Over Five Years Through Ten Years, Fair Value	852
Over Ten Years, Carrying Amount	836
Over Ten Years, Fair Value	850
Total securities held to maturity, carrying amount	1,683	1,738
Total securities held to maturity, Fair Value	$ 1,753	$ 1,785

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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