Share Incentive Plans - Summary of Terms of Each Retirement Eligibility Category (Details)	12 Months Ended
	Dec. 31, 2021
Age 62 for Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Eligibility	For employees hired prior to January 1, 2009 and who were age 59 or older as of February 1, 2019.
Effect on unvested restricted shares, restricted units and Options	Awards immediately vest and Options continue to be exercisable for the balance of the applicable ten-year option period.
Effect on LTI Plan	Awards are prorated in proportion to the number of days worked in the first year of the three-year performance period and the individual does not receive any payout of shares or units until the final payout is determined at the end of the three-year performance period.
Rule of 70 for Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Eligibility	All employees (1).
Effect on unvested restricted shares, restricted units and Options	Awards continue to vest per the original vesting schedule, subject to certain conditions, and Options continue to be exercisable for the balance of the applicable ten-year option period.
Effect on LTI Plan	Awards are prorated in proportion to the number of days worked in the first year of the three-year performance period and the individual does not receive any payout of shares or units until the final payout is determined at the end of the three-year performance period.
Age 72 for Trustees [Member]
Defined Benefit Plan Disclosure [Line Items]
Eligibility	All non-employee Trustees.
Effect on unvested restricted shares, restricted units and Options	Awards immediately vest and Options continue to be exercisable for the balance of the applicable ten-year option period.
Effect on LTI Plan	Awards are prorated in proportion to the number of days worked in the first year of the three-year performance period and the individual does not receive any payout of shares or units until the final payout is determined at the end of the three-year performance period.