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

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Securities Purchased under Agreements to Resell

($ In Millions)	2016			2015
Balance at December 31	$	1,967.5		$	1,600.0
Average Balance During the Year	1,764.1			1,144.7
Average Interest Rate Earned During the Year	1.04		%	0.54		%
Maximum Month-End Balance During the Year	2,050.9			1,600.0

Securities Sold under Agreements to Repurchase

($ In Millions)	2016			2015
Balance at December 31	$	473.7		$	546.6
Average Balance During the Year	847.1			649.5
Average Interest Rate Paid During the Year	0.27		%	0.05		%
Maximum Month-End Balance During the Year	565.5			802.4