Employee Benefit Plans - Narrative (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Treasury stock, shares repurchased	5.1		4.9		9.2
Cash payments for Restricted Stock Units	$ 24.1		$ 23.5		$ 22.1
Aggregate intrinsic value of stock options outstanding and exercisable	162.5
Options, vested and expected to vest, exercisable, aggregate intrinsic value	$ 130.9
Weighted average remaining life of stock options outstanding and exercisable	5 years
Options, exercisable, weighted average remaining contractual term	4 years
Aggregate intrinsic value for options exercised	$ 63.2		80.6		80.8
Defined benefit plan, accumulated benefit obligation	1,688.5		1,712.1
Accumulated other comprehensive income net gains (losses), after tax	286.1
Accumulated other comprehensive income net prior service cost (credit), after tax	$ 3.9
Minimum interest crediting rate	3.25%
Plan assets	$ 1,879.6		1,854.4		$ 1,800.5
Employer contributions	13.4		17.0
Expected future employer contributions, next fiscal year	13.8
Expected future plan benefit payment - 2025	136.0
Expected future plan benefit payment - 2026	150.0
Expected future plan benefit payment - 2027	153.7
Expected future plan benefit payment - 2028	126.0
Expected future plan benefit payment - 2029	128.5
Expected future plan benefit payment - 2030 to 2034	$ 669.5
Defined contribution plan, maximum annual contribution per employee, percent	50.00%
Highly compensated employee contribution percentage to retirement and saving plan	12.00%
Defined contribution plan, cost		$ 184.1		$ 163.6		$ 153.1
Time-based restricted shares/units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted	3 years
Performance Based Restricted Stock and Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Minimum percentage that will ultimately vest under performance-based restricted stock awards based on performance target	0.00%
Maximum percentage that will ultimately vest under performance-based restricted stock awards based on performance target	200.00%
Employee Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Purchase price of common stock as percentage of market value	95.00%
Non-Vested Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 2.9
Weighted-average remaining requisite vesting period	1 year
Restricted Stock Units (RSUs)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 186.9
Weighted-average remaining requisite vesting period	1 year 9 months 18 days
Non-Vested Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 11.3
Weighted-average remaining requisite vesting period	8 months 12 days
Cash and cash equivalents
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Plan assets	$ 10.4		$ 2.2
Minimum | Performance Based Restricted Stock and Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Performance period (years)	1 year
Maximum | Performance Based Restricted Stock and Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted	38 months
Performance period (years)	3 years