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Employee Share-Based Incentive Compensation Plans - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended		36 Months Ended
	Jun. 30, 2023 USD ($) shares	Jun. 30, 2022 USD ($) shares	Jun. 30, 2023 USD ($) shares	Jun. 30, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)
Performance Share | W T M Incentive Plan
Share-based compensation arrangement by share-based payment award
Vesting period			3 years
Performance cycle period			3 years
New grants (in shares) | shares	0	150	10,895	13,225	750
Additional compensation cost that would be recognized if all outstanding performance shares vested | $	$ 37.8		$ 37.8
Performance Share | Minimum | W T M Incentive Plan
Share-based compensation arrangement by share-based payment award
Share-based compensation arrangement by share-based payment award, multiplier			0
Performance Share | Maximum | W T M Incentive Plan
Share-based compensation arrangement by share-based payment award
Share-based compensation arrangement by share-based payment award, multiplier			2
Restricted Stock
Share-based compensation arrangement by share-based payment award
Vesting period			34 months
Restricted Stock | W T M Incentive Plan
Share-based compensation arrangement by share-based payment award
Additional compensation cost that would be recognized if all outstanding performance shares vested | $	$ 24.3	$ 23.0	$ 24.3	$ 23.0	$ 15.9	$ 28.3	$ 15.5	$ 26.5
Issued (in shares) | shares	0	150	10,895	13,225

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