Employee Benefits - Schedule of Reconciliation of Projected Benefit Obligation and Fair Value of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 1,073.2	$ 1,228.4
Interest cost	45.7	44.1
Benefits paid	(96.7)	(110.4)
Actuarial (gain) loss	106.5	(88.5)
Other	0.1	(0.4)
Benefit obligation at year end	1,128.8	1,073.2
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at prior year end	874.9	998.3
Actual return on plan assets	112.1	(27.8)
Employer contributions	9.7	15.2
Benefits paid	(96.7)	(110.4)
Other		(0.4)
Fair value of plan assets at year end	900.0	874.9
Funded status at year end	$ (228.8)	$ (198.3)