Financing Agreement - Summary of Activity Under Credit Arrangements, Excluding Acquired Borrowings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Total borrowings as of December 31	$ 1,726.0	$ 1,365.0	$ 1,600.1
Average outstanding borrowings during year	1,500.4	1,879.7	1,912.0
Maximum outstanding borrowings during year	$ 1,903.0	$ 2,370.6	$ 2,127.9
Weighted-average interest rate as of December 31	1.77%	2.30%	3.29%