Supplemental Guarantor Information - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 74.3		$ 86.3	$ 216.9	$ 103.6	$ 103.6
Accounts and notes receivable, net	488.2	$ 485.8	483.1
Inventories	387.5	355.3	356.9
Other current assets	89.4	116.1	114.5
Current assets held for sale	0.0	711.8	708.0
Total current assets	1,039.4		1,748.8
Property, plant and equipment, net	272.6		279.8
Other assets
Investments in subsidiaries	0.0		0.0
Goodwill	2,072.7		2,112.8	1,994.6
Intangibles, net	276.3		321.8
Long-term intercompany debt			0.0
Other non-current assets	145.5	136.0	180.9
Non-current assets held for sale	0.0	3,788.0	3,989.6
Total other assets	2,494.5		6,605.1
Total assets	3,806.5		8,633.7	11,534.8
Current liabilities
Accounts payable	378.6		321.5
Employee compensation and benefits	111.7		115.8
Other current liabilities	328.4	404.0	401.3
Current liabilities held for sale	0.0		360.8
Total current liabilities	818.7		1,199.4
Other liabilities
Long-term debt	787.6		1,440.7
Pension and other post-retirement compensation and benefits	90.0		96.4
Deferred tax liabilities	105.9	105.0	108.6
Other non-current liabilities	168.2		213.8
Non-current liabilities held for sale	0.0	$ 510.4	537.0
Total liabilities	1,970.4		3,595.9
Equity
Total equity	1,836.1		5,037.8	4,254.4	4,008.8
Total liabilities and equity	3,806.5		8,633.7
Eliminations
Current assets
Cash and cash equivalents	0.0		0.0	0.0	0.0
Accounts and notes receivable, net	0.0		0.0
Inventories	0.0		0.0
Other current assets	(15.4)		(9.2)
Current assets held for sale			0.0
Total current assets	(15.4)		(9.2)
Property, plant and equipment, net	0.0		0.0
Other assets
Investments in subsidiaries	(6,615.6)		(17,470.8)
Goodwill	0.0		0.0
Intangibles, net	0.0		0.0
Long-term intercompany debt			0.0
Other non-current assets	(1,303.6)		(1,889.4)
Non-current assets held for sale			0.0
Total other assets	(7,919.2)		(19,360.2)
Total assets	(7,934.6)		(19,369.4)
Current liabilities
Accounts payable	0.0		0.0
Employee compensation and benefits	0.0		0.0
Other current liabilities	(15.4)		(9.2)
Current liabilities held for sale			0.0
Total current liabilities	(15.4)		(9.2)
Other liabilities
Long-term debt	(1,303.6)		(1,889.4)
Pension and other post-retirement compensation and benefits	0.0		0.0
Deferred tax liabilities	0.0		0.0
Other non-current liabilities	0.0		0.0
Non-current liabilities held for sale			0.0
Total liabilities	(1,319.0)		(1,898.6)
Equity
Total equity	(6,615.6)		(17,470.8)
Total liabilities and equity	(7,934.6)		(19,369.4)
Parent Company Guarantor
Current assets
Cash and cash equivalents	0.1		0.0	0.0	0.0
Accounts and notes receivable, net	4.6		0.0
Inventories	0.0		0.0
Other current assets	3.4		10.8
Current assets held for sale			0.0
Total current assets	8.1		10.8
Property, plant and equipment, net	0.0		0.0
Other assets
Investments in subsidiaries	1,903.8		5,205.1
Goodwill	0.0		0.0
Intangibles, net	0.0		0.0
Long-term intercompany debt			0.0
Other non-current assets	23.3		2.2
Non-current assets held for sale			0.0
Total other assets	1,927.1		5,207.3
Total assets	1,935.2		5,218.1
Current liabilities
Accounts payable	0.9		1.4
Employee compensation and benefits	0.2		0.4
Other current liabilities	47.6		99.6
Current liabilities held for sale			0.0
Total current liabilities	48.7		101.4
Other liabilities
Long-term debt	29.9		48.4
Pension and other post-retirement compensation and benefits	0.0		0.0
Deferred tax liabilities	0.0		0.0
Other non-current liabilities	20.5		30.5
Non-current liabilities held for sale			0.0
Total liabilities	99.1		180.3
Equity
Total equity	1,836.1		5,037.8
Total liabilities and equity	1,935.2		5,218.1
Subsidiary Guarantor
Current assets
Cash and cash equivalents	0.0		0.0	0.0	0.0
Accounts and notes receivable, net	0.0		0.0
Inventories	0.0		0.0
Other current assets	0.0		1.8
Current assets held for sale			0.0
Total current assets	0.0		1.8
Property, plant and equipment, net	0.0		0.0
Other assets
Investments in subsidiaries	2,036.1		5,109.6
Goodwill	0.0		0.0
Intangibles, net	0.0		0.0
Long-term intercompany debt			0.0
Other non-current assets	0.0		94.1
Non-current assets held for sale			0.0
Total other assets	2,036.1		5,203.7
Total assets	2,036.1		5,205.5
Current liabilities
Accounts payable	0.0		0.0
Employee compensation and benefits	0.0		0.0
Other current liabilities	1.5		0.4
Current liabilities held for sale			0.0
Total current liabilities	1.5		0.4
Other liabilities
Long-term debt	130.8		0.0
Pension and other post-retirement compensation and benefits	0.0		0.0
Deferred tax liabilities	0.0		0.0
Other non-current liabilities	0.0		0.0
Non-current liabilities held for sale			0.0
Total liabilities	132.3		0.4
Equity
Total equity	1,903.8		5,205.1
Total liabilities and equity	2,036.1		5,205.5
Subsidiary Issuer
Current assets
Cash and cash equivalents	0.1		0.0	0.0	0.1
Accounts and notes receivable, net	0.0		0.0
Inventories	0.0		0.0
Other current assets	2.2		1.5
Current assets held for sale			0.0
Total current assets	2.3		1.5
Property, plant and equipment, net	0.0		0.0
Other assets
Investments in subsidiaries	2,675.7		7,156.1
Goodwill	0.0		0.0
Intangibles, net	0.0		0.0
Long-term intercompany debt			0.0
Other non-current assets	696.1		614.0
Non-current assets held for sale			0.0
Total other assets	3,371.8		7,770.1
Total assets	3,374.1		7,771.6
Current liabilities
Accounts payable	0.0		0.0
Employee compensation and benefits	0.0		0.0
Other current liabilities	4.4		9.4
Current liabilities held for sale			0.0
Total current liabilities	4.4		9.4
Other liabilities
Long-term debt	1,333.9		2,652.8
Pension and other post-retirement compensation and benefits	0.0		0.0
Deferred tax liabilities	0.0		0.0
Other non-current liabilities	0.0		0.0
Non-current liabilities held for sale			0.0
Total liabilities	1,338.3		2,662.2
Equity
Total equity	2,035.8		5,109.4
Total liabilities and equity	3,374.1		7,771.6
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	74.1		86.3	$ 216.9	$ 103.5
Accounts and notes receivable, net	483.6		483.1
Inventories	387.5		356.9
Other current assets	99.2		109.6
Current assets held for sale			708.0
Total current assets	1,044.4		1,743.9
Property, plant and equipment, net	272.6		279.8
Other assets
Investments in subsidiaries	0.0		0.0
Goodwill	2,072.7		2,112.8
Intangibles, net	276.3		321.8
Long-term intercompany debt			0.0
Other non-current assets	729.7		1,360.0
Non-current assets held for sale			3,989.6
Total other assets	3,078.7		7,784.2
Total assets	4,395.7		9,807.9
Current liabilities
Accounts payable	377.7		320.1
Employee compensation and benefits	111.5		115.4
Other current liabilities	290.3		301.1
Current liabilities held for sale			360.8
Total current liabilities	779.5		1,097.4
Other liabilities
Long-term debt	596.6		628.9
Pension and other post-retirement compensation and benefits	90.0		96.4
Deferred tax liabilities	105.9		108.6
Other non-current liabilities	147.7		183.3
Non-current liabilities held for sale			537.0
Total liabilities	1,719.7		2,651.6
Equity
Total equity	2,676.0		7,156.3
Total liabilities and equity	$ 4,395.7		$ 9,807.9