Balance Sheet Offsetting - Summary of Collateral Swaps (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total repurchase agreements
Total customer repurchase agreements	$ 409.1	$ 332.9	$ 301.6
Collateral Swaps [Member]
Total resale agreements
Gross Amount Recognized	450.0	450.0
Gross Amount Offset	(450.0)	(450.0)
Net Amount Presented	0.0	0.0
Total repurchase agreements
Gross Amount Recognized	450.0	450.0
Gross Amount Offset	(450.0)	(450.0)
Total customer repurchase agreements	$ 0.0	$ 0.0

Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset.

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