Stockholders' equity (Tables)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

Accumulated other comprehensive loss is as follows:

	Total		Translation Adjustments		Postretirement Plans
Balance at December 31, 2020	$	(3,939.5)	$	(826.6)	$	(3,112.9)
Other comprehensive income (loss) before reclassifications	58.6		(43.6)		102.2
Amounts reclassified from accumulated other comprehensive loss	616.8		4.0		612.8
Current period other comprehensive income (loss)	675.4		(39.6)		715.0
Balance at December 31, 2021	(3,264.1)		(866.2)		(2,397.9)
Other comprehensive income (loss) before reclassifications	38.0		(114.1)		152.1
Amounts reclassified from accumulated other comprehensive loss	150.1		2.9		147.2
Current period other comprehensive income (loss)	188.1		(111.2)		299.3
Balance at December 31, 2022	(3,076.0)		(977.4)		(2,098.6)
Other comprehensive (loss) income before reclassifications	(142.8)		68.3		(211.1)
Amounts reclassified from accumulated other comprehensive loss	418.5		(3.7)		422.2
Current period other comprehensive income	275.7		64.6		211.1
Balance at December 31, 2023	$	(2,800.3)	$	(912.8)	$	(1,887.5)

Schedule of Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss)

Amounts reclassified out of accumulated other comprehensive loss are as follows:

Year ended December 31,	2023		2022		2021
Translation adjustments:
Adjustment for substantial completion of liquidation of foreign subsidiaries(i)	$	(3.7)	$	2.9	$	4.0
Postretirement plans(ii):
Amortization of prior service credit	(5.4)		(5.8)		(6.2)
Amortization of actuarial losses	80.5		159.0		178.9
Settlement losses	348.9		—		499.4
Total before tax	420.3		156.1		676.1
Income tax	(1.8)		(6.0)		(59.3)
Total reclassifications for the period	$	418.5	$	150.1	$	616.8

(i) Reported in other (expense), net in the consolidated statements of income (loss).

(ii) Included in net periodic postretirement cost (see Note 17, “Employee plans”).

Schedule of Changes in Common Stock and Treasury Stock

The following table summarizes the changes in shares of common stock and treasury stock:

	Common Stock	Treasury Stock
Balance at December 31, 2020	66.8	3.8
Debt exchange	4.6	1.2
Stock-based compensation	1.1	0.3
Balance at December 31, 2021	72.5	5.3
Stock-based compensation	0.8	0.2
Balance at December 31, 2022	73.3	5.5
Stock-based compensation	0.7	0.1
Balance at December 31, 2023	74.0	5.6