Securities (Details 7) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	$ 792
Over One Year Through Five Years, Fair Value	806
Over Five Years Through Ten Years, Carrying Amount	884
Over Five Years Through Ten Years, Fair Value	905
Over Ten Years, Carrying Amount	8,698
Over Ten Years, Fair Value	8,637
Total securities held to maturity, carrying amount	10,374	$ 10,337
Total securities held to maturity, Fair Value	10,348	10,316
U.S. Treasury securities
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	493
Over One Year Through Five Years, Fair Value	497
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	493	492
Total securities held to maturity, Fair Value	497	497
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	326
Over Five Years Through Ten Years, Fair Value	324
Over Ten Years, Carrying Amount	7,980
Over Ten Years, Fair Value	7,916
Total securities held to maturity, carrying amount	8,306	8,263
Total securities held to maturity, Fair Value	8,240	$ 8,201
U.S. government agency and government-sponsored agencies - commercial mortgage-backed securities
Securities held to maturity
Over One Year Through Five Years, Carrying Amount	299
Over One Year Through Five Years, Fair Value	309
Over Five Years Through Ten Years, Carrying Amount	558
Over Five Years Through Ten Years, Fair Value	581
Over Ten Years, Carrying Amount	718
Over Ten Years, Fair Value	721
Total securities held to maturity, carrying amount	1,575
Total securities held to maturity, Fair Value	$ 1,611

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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