Amount of affordable housing tax credits and other tax benefits recognized.

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Amount of investment in qualified affordable housing projects.

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Amount of commitment or contingent commitments to qualified affordable housing project investments.

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Investments in Qualified Affordable Housing Projects, Federal Historical Projects and New Market Tax Credits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Remaining unfunded equity contributions	$ 128.1		$ 128.1		$ 56.2
Qualified Affordable Housing Projects
Schedule of Equity Method Investments [Line Items]
Amortization expense	3.6	$ 2.4	8.5	$ 7.2
Tax credits and other benefits	4.5	$ 2.9	10.5	$ 8.5
Remaining investment amount	231.4		231.4		$ 90.9
Federal Historical Projects
Schedule of Equity Method Investments [Line Items]
Remaining investment amount	$ 38.5		$ 38.5