Goodwill and Other Intangible Assets - Gross carrying amount, accumulated amortization and net book value of intangible assets other than goodwill (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	$ 157.6	$ 160.5
Finite-lived intangible assets, amortization amount	(38.3)	(38.9)
Intangible assets, book value	119.3	121.6
Indefinite-lived Intangible Assets
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	117.3	119.6
Intangible assets, book value	117.3	119.6
Indefinite-lived Intangible Assets | Distribution Network
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	19.1	19.6
Finite-lived intangible assets, book value	19.1	19.6
Indefinite-lived Intangible Assets | Trademarks and Tradenames
Intangible asset balances by major asset class
Indefinite-lived intangible assets, book value	98.2	100.0
Finite-Lived Intangible Assets
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	40.3	40.9
Finite-lived intangible assets, amortization amount	(38.3)	(38.9)
Intangible assets, book value	2.0	2.0
Finite-Lived Intangible Assets | Customer Relationships
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	9.8	9.9
Finite-lived intangible assets, amortization amount	(8.6)	(8.6)
Finite-lived intangible assets, book value	1.2	1.3
Finite-Lived Intangible Assets | Patents
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	30.5	31.0
Finite-lived intangible assets, amortization amount	(29.7)	(30.3)
Finite-lived intangible assets, book value	$ 0.8	$ 0.7