Employee Benefit Plans and Other Postretirement Plans - Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions	$ 57,100,000	$ 57,100,000	$ 400,000
Estimated Net Periodic Benefit Cost and Amortization of Other Comprehensive Income for The Next Year
Estimated net periodic benefit cost for 2016	12,700,000
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions	58,200,000	1,200,000
Components of net periodic benefit cost
Service cost	24,500,000	24,000,000	22,700,000
Interest cost	40,900,000	46,200,000	45,900,000
Expected return on plan assets	(49,500,000)	(53,100,000)	(50,700,000)
Special termination benefits	0	0	300,000
Net amortization of unrecognized amounts, Prior service cost	5,700,000	5,500,000	6,500,000
Net amortization of unrecognized amounts, Actuarial loss	5,800,000	8,700,000	600,000
Net periodic benefit cost	27,400,000	31,300,000	25,300,000
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net (gain) loss	40,400,000	(14,500,000)	146,400,000
Prior service cost (credit)	1,800,000	3,000,000	2,600,000
Amortization of prior service cost	(5,700,000)	(5,500,000)	(6,500,000)
Amortization of actuarial loss	(5,800,000)	(8,700,000)	(600,000)
Total recognized in other comprehensive (income) loss (b)	30,700,000	(25,700,000)	141,900,000
Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax	58,100,000	5,600,000	167,200,000
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Company contributions	1,400,000	2,000,000
Components of net periodic benefit cost
Service cost	500,000	1,700,000	1,600,000
Interest cost	600,000	1,200,000	1,200,000
Expected return on plan assets	0	0	0
Special termination benefits	0	0	0
Net amortization of unrecognized amounts, Prior service cost	(100,000)	100,000	(200,000)
Net amortization of unrecognized amounts, Actuarial loss	(400,000)	100,000	100,000
Net periodic benefit cost	600,000	3,100,000	2,700,000
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net (gain) loss	3,600,000	(11,400,000)	4,200,000
Prior service cost (credit)	(5,300,000)	0	0
Amortization of prior service cost	(300,000)	(100,000)	200,000
Amortization of actuarial loss	800,000	(100,000)	(100,000)
Total recognized in other comprehensive (income) loss (b)	(1,200,000)	(11,600,000)	4,300,000
Total recognized in net periodic benefit cost and other comprehensive (income) loss - pretax	$ (600,000)	$ (8,500,000)	$ 7,000,000