Borrowings Under Credit Facilities and Commercial Paper Program - Narrative (Details)	9 Months Ended
	Sep. 30, 2022 USD ($) term bank	Sep. 30, 2022 CAD ($) term bank	Dec. 31, 2021 USD ($)	[1]
Line of Credit Facility [Line Items]
Number of banks in consortium | bank	31	31
Borrowings outstanding	$ 654,715,000		$ 324,935,000
Outstanding balance	14,600,333,000
Unsecured revolving credit facility
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	4,000,000,000
Borrowings outstanding	$ 0
Number of successive terms | term	2	2
Successive term	6 months
Available to borrow in alternate currencies	$ 1,000,000,000
Facility fee	0.15%
Unsecured revolving credit facility | Credit Facility, Tranche Due 2026
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	$ 1,000,000,000
Borrowings outstanding	0
Unsecured revolving credit facility | Credit Facility, Tranche Due 2025
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	3,000,000,000
Borrowings outstanding	$ 40,000,000
Unsecured revolving credit facility | SOFR
Line of Credit Facility [Line Items]
Interest rate margin	0.775%
Unsecured revolving credit facility | Accordion feature
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	$ 1,250,000,000
Term credit facility
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	1,000,000,000
Term credit facility, CAD denominated
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement		$ 250,000,000
Term credit facility, CAD denominated | Accordion feature
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement		$ 250,000,000
Commercial paper note program
Line of Credit Facility [Line Items]
Unsecured line of credit arrangement	$ 1,000,000,000
Commercial paper note program | Maximum
Line of Credit Facility [Line Items]
Debt instrument, term	397 days
Commercial paper note program | Line of Credit
Line of Credit Facility [Line Items]
Outstanding balance	$ 614,715,000
Principal outstanding	615,000,000
Unamortized discount	$ 285,000
Weighted average interest rate	3.43%	3.43%
Commercial paper note program | Line of Credit | Weighted Average
Line of Credit Facility [Line Items]
Debt instrument, term	6 days

[1] The consolidated balance sheet at December 31, 2021 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements.