Employee Benefits - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) trust shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Total cost for retirement plans	$ 170.0	$ 124.0	$ 93.0
Defined contribution plan cost	120.0	88.0	86.0
Pension trust assets	$ 1,473.0	1,464.0
U.S.
Defined Benefit Plan Disclosure [Line Items]
Number of pension trust accounts | trust	1
Pension trust assets	$ 1,176.0	$ 1,185.0
Stock purchased by US plan under defined contribution plan (shares) | shares	146,600	67,248
Stock sold by US plan under defined contribution plan (shares) | shares	179,569	60,473
Stock held by the US plan under defined contribution plan (shares) | shares	1,200,000	1,200,000
Market value of stock held by the US plan under defined contribution plan	$ 518.0	$ 402.0
S&P Global Inc. dividends received	$ 4.5	4.0
U.S. | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	90.00%
U.S. | Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	5.00%
U.S. | International equities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	3.00%
U.S. | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	2.00%
U.K.
Defined Benefit Plan Disclosure [Line Items]
Number of pension trust accounts | trust	1
Pension trust assets	$ 297.0	279.0
U.K. | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	67.00%
U.K. | Equities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	16.00%
U.K. | Real estate
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	12.00%
U.K. | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations	5.00%
Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (benefit)	$ 4.0	(8.0)	(36.0)
Expected required employer contribution	$ 11.0
Number of pension trust accounts | trust	2
Pension trust assets	$ 1,473.0	1,464.0	2,231.0
Retirement Plans | U.K.
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (benefit)	4.0	(6.0)	(22.0)
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (benefit)	(3.0)	(3.0)	(2.0)
Expected required employer contribution	3.0
Pension trust assets	$ 1.0	$ 5.0	$ 6.0