Securities (Details 7) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	$ 539
Over One Year Through Five Years, Fair Value	556
Over Five Years Through Ten Years, Carrying Amount	888
Over Five Years Through Ten Years, Fair Value	963
Over Ten Years, Carrying Amount	8,832
Over Ten Years, Fair Value	9,054
Total securities held to maturity, carrying amount	10,259	$ 10,158
Total securities held to maturity, Fair Value	10,573	10,207
U.S. Treasury
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	490
Over One Year Through Five Years, Fair Value	505
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	490	489
Total securities held to maturity, Fair Value	505	493
U.S. government sponsored agencies
Securities held to maturity
Total securities held to maturity, carrying amount		220
Total securities held to maturity, Fair Value		216
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	86
Over Five Years Through Ten Years, Fair Value	88
Over Ten Years, Carrying Amount	8,040
Over Ten Years, Fair Value	8,241
Total securities held to maturity, carrying amount	8,126	7,782
Total securities held to maturity, Fair Value	8,329	7,790
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	802
Over Five Years Through Ten Years, Fair Value	875
Over Ten Years, Carrying Amount	792
Over Ten Years, Fair Value	813
Total securities held to maturity, carrying amount	1,643	1,667
Total securities held to maturity, Fair Value	$ 1,739	$ 1,708

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

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