Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount of assets pledged to secure a debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Senior unsecured notes and secured debt.

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Senior Unsecured Notes and Secured Debt - Annual Principal Payments Due on Debt Obligations (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 CAD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Principal payments due on debt obligations
2022	$ 582,884,000
2023	1,247,380,000
2024	1,531,710,000
2025	1,420,427,000
2026	807,327,000
Thereafter	8,320,545,000
Totals	13,910,273,000			$ 2,378,073,000
Senior Unsecured Notes
Principal payments due on debt obligations
2022	0
2023	695,664,000
2024	1,350,000,000
2025	1,260,000,000
2026	700,000,000
Thereafter	7,702,297,000
Totals	$ 11,707,961,000			11,509,533,000	$ 10,427,562,000	$ 9,699,984,000
Senior Unsecured Notes \| Minimum
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	0.80%	0.80%	0.80%
Senior Unsecured Notes \| Maximum
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	6.50%	6.50%	6.50%
Secured Debt
Principal payments due on debt obligations
2022	$ 582,884,000
2023	551,716,000
2024	181,710,000
2025	160,427,000
2026	107,327,000
Thereafter	618,248,000
Totals	2,202,312,000			$ 2,378,073,000	$ 2,993,342,000	$ 2,485,711,000
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Carrying value of properties securing the debt	$ 5,062,000,000
Secured Debt \| Minimum
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	0.08%	0.08%	0.08%
Secured Debt \| Maximum
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	6.67%	6.67%	6.67%
Term Loan \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Face amount	$ 195,664,000	$ 250,000,000
Term Loan \| Canadian Dealer Offered Rate \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate margin	0.90%
Effective rate	1.34%	1.34%	1.34%
Unsecured term credit facility Matures July 19 2023 \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Face amount	$ 500,000,000
Unsecured term credit facility Matures July 19 2023 \| LIBOR \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate margin	0.90%
Effective rate	1.00%	1.00%	1.00%
2.95% Senior Unsecured Notes Due 2023 \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	2.95%	2.95%	2.95%
Face amount	$ 234,797,000	$ 300,000,000
UK Debt Due 2028 \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	4.80%	4.80%	4.80%
Face amount	$ 742,500,000		£ 550,000,000
4.50% Senior Unsecured Notes Due 2034 \| Senior Unsecured Notes
Senior Unsecured Notes and Secured Debt Textual [Abstract]
Interest rate	4.50%	4.50%	4.50%
Face amount	$ 675,000,000		£ 500,000,000