Segment Reporting - Reconciliation of Reportable Segment ROA Pre-Tax Profit to Consolidated Income before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Income before income taxes	$ 440.6	$ 387.6	$ 1,270.4	$ 1,163.8
U.S. reportable segment
Segment Reporting Information [Line Items]
U.S. ROA pre-tax profit	380.5	333.8	1,100.2	1,007.1
Other operating segment
Segment Reporting Information [Line Items]
Other operating segment pre-tax profit	$ 60.1	$ 53.8	$ 170.2	$ 156.7