Securities Purchased Under Agreements to Resell and Securities Sold Under Agreements to Repurchase (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Securities Purchased under Agreements to Resell

($ In Millions)	2020			2019
Balance at December 31	$	1,596.5		$	707.8
Average Balance During the Year	1,253.1			835.0
Average Interest Rate Earned During the Year	0.31		%	2.10		%
Maximum Month-End Balance During the Year	$	2,055.6		$	1,290.0

Securities Sold under Agreements to Repurchase

($ In Millions)	2020			2019
Balance at December 31	$	39.8		$	489.7
Average Balance During the Year	218.3			339.0
Average Interest Rate Paid During the Year	0.47		%	1.89		%
Maximum Month-End Balance During the Year	$	269.8		$	489.7

Transfer of Certain Financial Assets Accounted for as Secured Borrowings

	REMAINING CONTRACTUAL MATURITY OF THE AGREEMENTS
	OVERNIGHT AND CONTINUOUS
($ In Millions)	December 31, 2020		December 31, 2019
U.S. Treasury and Agency Securities	$	39.8	$	489.7
Total Borrowings	39.8		489.7
Gross Amount of Recognized Liabilities for Repurchase Agreements in Note 28	39.8		489.7
Amounts related to agreements not included in Note 28	—		—