Discontinued Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 01, 2016	Dec. 04, 2014
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Initial term of campus lease agreement period		5 years
Accumulated other comprehensive losses, net of tax		$ (403.8)	$ (487.4)
Pension liabilities, including an unfunded pension liability		86.3	62.1
Income tax (benefit)		(15.2)	(41.8)	$ (2.5)
U.S. Defined Benefit Pension Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Defined benefit plan, liability transferred		365.2
U.S. Postretirement Benefit Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Defined benefit plan, liability transferred		86.3
AFI [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Dividends received					$ 50.0
Income tax (benefit)		0.1	17.8	$ 13.9
AFI [Member] | Transferring To AFI [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Defined benefit plan, liability transferred		365.2
Defined benefit plan, net liability transferred		3.0
Defined benefit plan, plan assets transferred		362.2
Accumulated other comprehensive losses, net of tax					$ 60.0
Reduction in additional paid-in capital		656.1
AFI [Member] | Transferring To AFI [Member] | U.S. Defined Benefit Pension Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Defined benefit plan, liability transferred		3.0
AFI [Member] | Transferring To AFI [Member] | U.S. Postretirement Benefit Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Defined benefit plan, liability transferred		86.3
DLW [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Pension liabilities, including an unfunded pension liability	$ 115.0
Income tax (benefit)	$ (43.4)
Contingent liability						$ 12.9
Assets removed from balance sheet						151.9
Liabilities removed from balance sheet						$ 164.8
DLW [Member] | Accounts Payable and Accrued Expenses [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Contingent liability		$ 11.9	$ 12.1