Stockholders' equity - Class of Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2022	Nov. 11, 2022	Dec. 31, 2021
Equity [Abstract]
Shares of common stock repurchased (in shares)	1,800,000	4,400,000	2,600,000
Average price paid per share (in dollars per share)	$ 42.36		$ 42.67
Total cost	$ 75.5	$ 187.9	$ 112.6

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Balance Type:	debit
Period Type:	duration