Supplemental Guarantor Information - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 82.5	$ 74.3	$ 86.3	$ 216.9
Accounts and notes receivable, net	502.9	488.2
Inventories	377.4	387.5
Other current assets	99.1	89.4
Total current assets	1,061.9	1,039.4
Property, plant and equipment, net	283.2	272.6
Other assets
Investments in subsidiaries	0.0	0.0
Goodwill	2,258.3	2,072.7	2,112.8
Intangibles, net	339.2	276.3
Other non-current assets	196.9	145.5
Total other assets	2,794.4	2,494.5
Total assets	4,139.5	3,806.5	8,633.7
Current liabilities
Accounts payable	325.1	378.6
Employee compensation and benefits	71.0	111.7
Other current liabilities	352.9	328.4
Total current liabilities	749.0	818.7
Other liabilities
Long-term debt	1,029.1	787.6
Pension and other post-retirement compensation and benefits	96.4	90.0
Deferred tax liabilities	104.4	105.9
Other non-current liabilities	206.7	168.2
Total liabilities	2,185.6	1,970.4
Equity
Total equity	1,953.9	1,836.1	5,037.8	4,254.4
Total liabilities and equity	4,139.5	3,806.5
Eliminations
Current assets
Cash and cash equivalents	0.0	0.0	0.0	0.0
Accounts and notes receivable, net	(0.8)	0.0
Inventories	0.0	0.0
Other current assets	0.0	(15.4)
Total current assets	(0.8)	(15.4)
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	(6,598.1)	(6,615.6)
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	(1,377.4)	(1,303.6)
Total other assets	(7,975.5)	(7,919.2)
Total assets	(7,976.3)	(7,934.6)
Current liabilities
Accounts payable	(0.8)	0.0
Employee compensation and benefits	0.0	0.0
Other current liabilities	0.0	(15.4)
Total current liabilities	(0.8)	(15.4)
Other liabilities
Long-term debt	(1,377.4)	(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	(1,378.2)	(1,319.0)
Equity
Total equity	(6,598.1)	(6,615.6)
Total liabilities and equity	(7,976.3)	(7,934.6)
Parent Company Guarantor
Current assets
Cash and cash equivalents	0.0	0.1	0.0	0.0
Accounts and notes receivable, net	0.2	4.6
Inventories	0.0	0.0
Other current assets	1.2	3.4
Total current assets	1.4	8.1
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	1,904.5	1,903.8
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	110.6	23.3
Total other assets	2,015.1	1,927.1
Total assets	2,016.5	1,935.2
Current liabilities
Accounts payable	2.4	0.9
Employee compensation and benefits	0.1	0.2
Other current liabilities	39.7	47.6
Total current liabilities	42.2	48.7
Other liabilities
Long-term debt	0.0	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	20.4	20.5
Total liabilities	62.6	99.1
Equity
Total equity	1,953.9	1,836.1
Total liabilities and equity	2,016.5	1,935.2
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	0.0
Total current assets	0.0	0.0
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	1,904.0	2,036.1
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	0.9	0.0
Total other assets	1,904.9	2,036.1
Total assets	1,904.9	2,036.1
Current liabilities
Accounts payable	0.1	0.0
Employee compensation and benefits	0.0	0.0
Other current liabilities	0.3	1.5
Total current liabilities	0.4	1.5
Other liabilities
Long-term debt	0.0	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	0.4	132.3
Equity
Total equity	1,904.5	1,903.8
Total liabilities and equity	1,904.9	2,036.1
Subsidiary Issuer
Current assets
Cash and cash equivalents	0.1	0.1	0.0	0.0
Accounts and notes receivable, net	2.4	0.0
Inventories	0.0	0.0
Other current assets	0.2	2.2
Total current assets	2.7	2.3
Property, plant and equipment, net	0.0	0.0
Other assets
Investments in subsidiaries	2,789.6	2,675.7
Goodwill	0.0	0.0
Intangibles, net	0.0	0.0
Other non-current assets	1,278.7	696.1
Total other assets	4,068.3	3,371.8
Total assets	4,071.0	3,374.1
Current liabilities
Accounts payable	0.1	0.0
Employee compensation and benefits	0.0	0.0
Other current liabilities	13.1	4.4
Total current liabilities	13.2	4.4
Other liabilities
Long-term debt	2,154.0	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	2,167.2	1,338.3
Equity
Total equity	1,903.8	2,035.8
Total liabilities and equity	4,071.0	3,374.1
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	82.4	74.1	$ 86.3	$ 216.9
Accounts and notes receivable, net	501.1	483.6
Inventories	377.4	387.5
Other current assets	97.7	99.2
Total current assets	1,058.6	1,044.4
Property, plant and equipment, net	283.2	272.6
Other assets
Investments in subsidiaries	0.0	0.0
Goodwill	2,258.3	2,072.7
Intangibles, net	339.2	276.3
Other non-current assets	184.1	729.7
Total other assets	2,781.6	3,078.7
Total assets	4,123.4	4,395.7
Current liabilities
Accounts payable	323.3	377.7
Employee compensation and benefits	70.9	111.5
Other current liabilities	299.8	290.3
Total current liabilities	694.0	779.5
Other liabilities
Long-term debt	252.5	596.6
Pension and other post-retirement compensation and benefits	96.4	90.0
Deferred tax liabilities	104.4	105.9
Other non-current liabilities	186.3	147.7
Total liabilities	1,333.6	1,719.7
Equity
Total equity	2,789.8	2,676.0
Total liabilities and equity	$ 4,123.4	$ 4,395.7