Securities - Remaining Maturity of Securities Held to Maturity (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Held to Maturity - Amortized Cost
Due in One Year or Less	$ 6,638.2	$ 5,691.9
Due After One Year Through Five Years	7,066.0	6,667.8
Due After Five Years Through Ten Years	567.9	612.2
Due After Ten Years	81.9	77.1
AMORTIZED COST	14,354.0	13,049.0
Held to Maturity - Fair Value
Due in One Year or Less	6,635.5	5,695.8
Due After One Year Through Five Years	7,040.0	6,663.9
Due After Five Years Through Ten Years	553.0	606.3
Due After Ten Years	38.5	44.9
FAIR VALUE	$ 14,267.0	$ 13,010.9

Amount of investment in debt security measured at amortized cost (held-to-maturity).

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