Postretirement Health Care and Life Insurance Benefits (Details) - Postretirement Health Care and Life Insurance Benefits [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic postretirement benefit cost
Service cost for benefits earned		$ 10.4	$ 11.2	$ 12.2
Interest cost on accumulated postretirement benefit obligation		34.5	33.8	36.4
Amortization of prior service (credit) cost		(9.2)	(6.8)	1.3
Amortization of actuarial loss		20.4	24.9	14.5
Special termination benefits	[1]	0.0	0.0	1.6
Total net periodic postretirement or pension cost		$ 56.1	$ 63.1	$ 66.0

[1] Reflected in "Restructuring and pension settlement charges" in the consolidated statement of operations for the year ended December 31, 2014.