Earnings per Share (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted average common shares outstanding - basic	94,000,000	112,000,000	100,000,000	112,000,000
Dilutive effect of employee stock plans	0	1,000,000	1,000,000
Shares used for diluted earnings per share	94,000,000	113,000,000	101,000,000	113,000,000
Net income per share - basic	$ 3.90	$ 1.58	$ 11.81	$ 2.16
Net income per share - diluted	$ 3.87	$ 1.57	$ 11.73	$ 2.15