Supplemental Guarantor Information - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 78.9	$ 74.3	$ 70.8	$ 86.3
Accounts and notes receivable, net	645.7	488.2
Inventories	421.8	387.5
Other current assets	105.2	89.4
Total current assets	1,251.6	1,039.4
Property, plant and equipment, net	279.1	272.6
Other assets
Investments in subsidiaries	0.0	0.0
Goodwill	2,283.0	2,072.7
Intangibles, net	361.5	276.3
Other non-current assets	207.0	145.5
Total other assets	2,851.5	2,494.5
Total assets	4,382.2	3,806.5
Current liabilities
Accounts payable	265.3	378.6
Employee compensation and benefits	94.2	111.7
Other current liabilities	345.8	328.4
Total current liabilities	705.3	818.7
Other liabilities
Long-term debt	1,370.7	787.6
Pension and other post-retirement compensation and benefits	89.8	90.0
Deferred tax liabilities	124.6	105.9
Other non-current liabilities	221.4	168.2
Total liabilities	2,511.8	1,970.4
Equity
Total equity	1,870.4	1,836.1	4,719.7	5,037.8
Total liabilities and equity	4,382.2	3,806.5
Parent Company Guarantor
Current assets
Cash and cash equivalents	0.1	0.1	0.2	0.0
Accounts and notes receivable, net	0.0	4.6
Inventories	0.0	0.0
Other current assets	3.1	3.4
Total current assets	3.2	8.1
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	1,965.9	1,903.8
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	23.4	23.3
Total other assets	1,989.3	1,927.1
Total assets	1,992.5	1,935.2
Current liabilities
Accounts payable	6.3	0.9
Employee compensation and benefits	0.3	0.2
Other current liabilities	35.7	47.6
Total current liabilities	42.3	48.7
Other liabilities
Long-term debt	59.7	29.9
Pension and other post-retirement compensation and benefits	0.0	0.0
Deferred tax liabilities	0.0	0.0
Other non-current liabilities	20.1	20.5
Total liabilities	122.1	99.1
Equity
Total equity	1,870.4	1,836.1
Total liabilities and equity	1,992.5	1,935.2
Guarantor Subsidiaries
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	0.0
Total current assets	0.0	0.0
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	2,099.7	2,036.1
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	0.0	0.0
Total other assets	2,099.7	2,036.1
Total assets	2,099.7	2,036.1
Current liabilities
Accounts payable	0.0	0.0
Employee compensation and benefits	0.1	0.0
Other current liabilities	1.3	1.5
Total current liabilities	1.4	1.5
Other liabilities
Long-term debt	132.4	130.8
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
Total liabilities	133.8	132.3
Equity
Total equity	1,965.9	1,903.8
Total liabilities and equity	2,099.7	2,036.1
Subsidiary Issuer
Current assets
Cash and cash equivalents	0.0	0.1	0.0	0.0
Accounts and notes receivable, net	6.3	0.0
Inventories	0.0	0.0
Other current assets	0.1	2.2
Total current assets	6.4	2.3
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	2,740.2	2,675.7
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	1,319.5	696.1
Total other assets	4,059.7	3,371.8
Total assets	4,066.1	3,374.1
Current liabilities
Accounts payable	0.0	0.0
Employee compensation and benefits	0.0	0.0
Other current liabilities	6.7	4.4
Total current liabilities	6.7	4.4
Other liabilities
Long-term debt	1,959.9	1,333.9
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
Total liabilities	1,966.6	1,338.3
Equity
Total equity	2,099.5	2,035.8
Total liabilities and equity	4,066.1	3,374.1
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	78.8	74.1	70.6	86.3
Accounts and notes receivable, net	645.7	483.6
Inventories	421.8	387.5
Other current assets	102.0	99.2
Total current assets	1,248.3	1,044.4
Property, plant and equipment, net	279.1	272.6
Other assets
Investments in subsidiaries	0.0	0.0
Goodwill	2,283.0	2,072.7
Intangibles, net	361.5	276.3
Other non-current assets	813.1	729.7
Total other assets	3,457.6	3,078.7
Total assets	4,985.0	4,395.7
Current liabilities
Accounts payable	265.3	377.7
Employee compensation and benefits	93.8	111.5
Other current liabilities	302.1	290.3
Total current liabilities	661.2	779.5
Other liabilities
Long-term debt	1,167.7	596.6
Pension and other post-retirement compensation and benefits	89.8	90.0
Deferred tax liabilities	124.6	105.9
Other non-current liabilities	201.3	147.7
Total liabilities	2,244.6	1,719.7
Equity
Total equity	2,740.4	2,676.0
Total liabilities and equity	4,985.0	4,395.7
Consolidation, Eliminations
Current assets
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Accounts and notes receivable, net	(6.3)	0.0
Inventories	0.0	0.0
Other current assets	0.0	(15.4)
Total current assets	(6.3)	(15.4)
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	(6,805.8)	(6,615.6)
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	(1,949.0)	(1,303.6)
Total other assets	(8,754.8)	(7,919.2)
Total assets	(8,761.1)	(7,934.6)
Current liabilities
Accounts payable	(6.3)	0.0
Employee compensation and benefits	0.0	0.0
Other current liabilities	0.0	(15.4)
Total current liabilities	(6.3)	(15.4)
Other liabilities
Long-term debt	(1,949.0)	(1,303.6)
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
Total liabilities	(1,955.3)	(1,319.0)
Equity
Total equity	(6,805.8)	(6,615.6)
Total liabilities and equity	$ (8,761.1)	$ (7,934.6)