Share-Based Payments - Non-vested (Details) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
RSUs and DSUs
Units
Non-vested awards outstanding at the beginning of the period (in shares)	1.0
Granted (in shares)	0.6
Vested (in shares)	(0.2)
Forfeited (in shares)	(0.1)
Adjustment for performance results achieved (in shares)	0.0
Non-vested awards outstanding at the end of the period (in shares)	1.3	1.0
Weighted-average grant date fair value per unit
Nonvested awards, weighted-average grant date fair value per unit at beginning of period (in dollars per share)	$ 56.21
Granted (in dollars per share)	45.88
Vested (in dollars per share)	68.89
Forfeited (in dollars per share)	49.87
Adjustment for performance results achieved (in dollars per share)	0
Nonvested awards, weighted-average grant date fair value per unit at end of period (in dollars per share)	$ 49.23	$ 56.21
PSUs
Units
Non-vested awards outstanding at the beginning of the period (in shares)	0.7
Granted (in shares)	0.4	0.3	0.3
Vested (in shares)	0.0
Forfeited (in shares)	(0.1)
Adjustment for performance results achieved (in shares)	(0.2)
Non-vested awards outstanding at the end of the period (in shares)	0.8	0.7
Weighted-average grant date fair value per unit
Nonvested awards, weighted-average grant date fair value per unit at beginning of period (in dollars per share)	$ 58.12
Granted (in dollars per share)	45.71	$ 52.60	$ 53.31
Vested (in dollars per share)	0
Forfeited (in dollars per share)	49.44
Adjustment for performance results achieved (in dollars per share)	78.28
Nonvested awards, weighted-average grant date fair value per unit at end of period (in dollars per share)	$ 49.47	$ 58.12