Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Schedule Of Capital Stock

Changes to the number of shares of capital stock issued were as follows:

	Common stock issued		Exchangeable shares issued
	Class A	Class B	Class A	Class B
	(Share amounts in millions)
Balance as of December 31, 2018	2.6	205.4	2.8	14.8
Shares issued under equity compensation plans	—	0.2	—	—
Shares exchanged for common stock	—	0.1	—	(0.1)
Shares exchanged for Class B exchangeable shares	—	—	(0.1)	0.1
Balance as of December 31, 2019	2.6	205.7	2.7	14.8
Shares issued under equity compensation plans	—	0.4	—	—
Shares exchanged for common stock	—	3.7	—	(3.7)
Balance as of December 31, 2020	2.6	209.8	2.7	11.1
Shares issued under equity compensation plans	—	0.3	—	—
Balance as of December 31, 2021	2.6	210.1	2.7	11.1