CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Non-controlling Interest
Beginning Balance (in shares) at Dec. 31, 2019		226,900		35,300
Beginning Balance at Dec. 31, 2019	$ 9,993.6	$ 2.0	$ 7,877.2	$ (807.1)	$ 3,267.0	$ (382.6)	$ 37.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends	(23.0)				(23.0)
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax (in shares)				200
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax	(5.7)		(7.9)	$ 2.2
Stock based compensation	10.0		10.0
Net income (loss)	111.2				111.6		(0.4)
Other comprehensive income (loss), net of tax	(178.0)					(178.0)
Stock repurchase (in shares)				(1,600)
Stock repurchase	(105.3)			$ (105.3)
Other	(5.1)		(4.3)				(0.8)
Ending Balance (in shares) at Mar. 31, 2020		226,900		36,700
Ending Balance at Mar. 31, 2020	9,797.7	$ 2.0	7,875.0	$ (910.2)	3,355.6	(560.6)	35.9
Beginning Balance (in shares) at Dec. 31, 2019		226,900		35,300
Beginning Balance at Dec. 31, 2019	9,993.6	$ 2.0	7,877.2	$ (807.1)	3,267.0	(382.6)	37.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	197.0
Other comprehensive income (loss), net of tax	(155.2)
Ending Balance (in shares) at Jun. 30, 2020		226,900		36,600
Ending Balance at Jun. 30, 2020	9,880.6	$ 2.0	7,871.7	$ (909.3)	3,419.0	(537.8)	35.0
Beginning Balance (in shares) at Mar. 31, 2020		226,900		36,700
Beginning Balance at Mar. 31, 2020	9,797.7	$ 2.0	7,875.0	$ (910.2)	3,355.6	(560.6)	35.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends	(23.4)				(23.4)
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax (in shares)				100
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax	0.3		(0.6)	$ 0.9
Stock based compensation	(2.7)		(2.7)
Net income (loss)	85.8				86.8		(1.0)
Other comprehensive income (loss), net of tax	22.8					22.8
Other	0.1		0.0				0.1
Ending Balance (in shares) at Jun. 30, 2020		226,900		36,600
Ending Balance at Jun. 30, 2020	9,880.6	$ 2.0	7,871.7	$ (909.3)	3,419.0	(537.8)	35.0
Beginning Balance (in shares) at Dec. 31, 2020		226,900		38,000
Beginning Balance at Dec. 31, 2020	10,152.7	$ 2.0	7,880.6	$ (1,010.1)	3,588.9	(339.1)	30.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends	(23.0)				(23.0)
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax	(5.2)		(5.4)	0.2
Stock based compensation	8.7		8.7
Net income (loss)	114.7				112.4		2.3
Other comprehensive income (loss), net of tax	(69.9)					(69.9)
Stock repurchase	(1.2)			$ (1.2)
Other	0.3						0.3
Ending Balance (in shares) at Mar. 31, 2021		226,900		38,000
Ending Balance at Mar. 31, 2021	10,177.1	$ 2.0	7,883.9	$ (1,011.1)	3,678.3	(409.0)	33.0
Beginning Balance (in shares) at Dec. 31, 2020		226,900		38,000
Beginning Balance at Dec. 31, 2020	10,152.7	$ 2.0	7,880.6	$ (1,010.1)	3,588.9	(339.1)	30.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	239.9
Other comprehensive income (loss), net of tax	(36.7)
Ending Balance (in shares) at Jun. 30, 2021		226,900		37,900
Ending Balance at Jun. 30, 2021	10,327.8	$ 2.0	7,896.7	$ (1,008.6)	3,780.1	(375.8)	33.4
Beginning Balance (in shares) at Mar. 31, 2021		226,900		38,000
Beginning Balance at Mar. 31, 2021	10,177.1	$ 2.0	7,883.9	$ (1,011.1)	3,678.3	(409.0)	33.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends	(23.0)				(23.0)
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax (in shares)				100
Proceeds from treasury stock issued from the exercise of stock options and other benefit plans, net of tax	1.4		(1.1)	$ 2.5
Stock based compensation	13.9		13.9
Net income (loss)	125.2				124.8	0.0	0.4
Other comprehensive income (loss), net of tax	33.2					33.2
Stock repurchase	0.0
Other	0.0
Ending Balance (in shares) at Jun. 30, 2021		226,900		37,900
Ending Balance at Jun. 30, 2021	$ 10,327.8	$ 2.0	$ 7,896.7	$ (1,008.6)	$ 3,780.1	$ (375.8)	$ 33.4