Borrowings Under Credit Facilities and Commercial Paper Program - Narrative (Details)	1 Months Ended	3 Months Ended
	Jan. 31, 2019 USD ($)	Mar. 31, 2022 USD ($) bank term	Dec. 31, 2021 USD ($)
Line of Credit Facility [Line Items]
Number of banks in consortium | bank		34
Borrowings outstanding		$ 299,968,000	$ 324,935,000
Outstanding balance		14,347,236,000
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
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 2023
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		$ 110,000,000
Unsecured revolving credit facility | LIBOR
Line of Credit Facility [Line Items]
Interest rate during period		1.23%
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		500,000,000
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		189,968,000
Principal outstanding		190,000,000
Unamortized discount		$ 32,000
Weighted average interest rate		0.94%
Commercial paper note program | Line of Credit | Weighted Average
Line of Credit Facility [Line Items]
Debt instrument, term		7 days