Share repurchase program (Details) - USD ($) $ / shares in Units, shares in Millions					1 Months Ended	3 Months Ended
	Feb. 22, 2024	Nov. 13, 2023	Nov. 09, 2023	Jun. 02, 2023	Dec. 31, 2023	Mar. 31, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares repurchased under share repurchase program (in shares)						5.7
Shares repurchased value under share repurchase program						$ 82,400,000
Treasury stock, value, acquired, cost method						82,400,000
Dividends						19,900,000
Return of capital to shareholders						$ 102,300,000
Number of shares repurchased (in shares)						5.7
300 Million First Accelerated Share Repurchase Program
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares approved to be repurchased under share repurchase program, amount (up to)				$ 300,000,000
Shares repurchased under share repurchase program (in shares)				15.2			3.1
Shares repurchased value under share repurchase program				$ 240,000,000
Treasury stock, value, acquired, cost method				$ 240,000,000
Stock repurchase program, percent repurchased				80.00%
Number of shares repurchased (in shares)				15.2			3.1
325 Million Second Accelerated Share Repurchase
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares approved to be repurchased under share repurchase program, amount (up to)			$ 325,000,000
Shares repurchased under share repurchase program (in shares)	4.0	17.3	17.3			4.0
Shares repurchased value under share repurchase program		$ 260,000,000
Treasury stock, value, acquired, cost method		$ 260,000,000
Stock repurchase program, percent repurchased		80.00%
Number of shares repurchased (in shares)	4.0	17.3	17.3			4.0
December2023 Share Repurchase Program
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares approved to be repurchased under share repurchase program, amount (up to)					$ 650,000,000
Shares repurchased under share repurchase program (in shares)						5.8
Shares repurchased value under share repurchase program						$ 84,500,000
Treasury stock value acquired not yet have been paid						$ 2,100,000
Average price paid per share (in dollar per share)						$ 14.5
Treasury stock, value, acquired, cost method						$ 84,500,000
Share repurchase program expiration date					Dec. 31, 2025
Number of shares repurchased (in shares)						5.8