Debt and Credit Facilities - Additional Information (Details) - USD ($)		1 Months Ended
	Jul. 30, 2020	Nov. 30, 2020	Nov. 30, 2019	Dec. 31, 2020	Jul. 31, 2020	Mar. 31, 2020
364 Day Credit Agreement Expiring 2022 [Member]
Line Of Credit Facility [Line Items]
Initiation date		2020-11
Maximum borrowing capacity		$ 5,000,000,000.0
Credit facilities amount outstanding				$ 0		$ 0
Three Year Agreement Expiring 2023 [Member]
Line Of Credit Facility [Line Items]
Initiation date			2019-11
Maximum borrowing capacity			$ 5,000,000,000.0
Credit facilities amount outstanding				0		0
Five Year Agreement Expiring 2025 [Member]
Line Of Credit Facility [Line Items]
Initiation date			2019-11
Maximum borrowing capacity			$ 5,000,000,000.0
Credit facilities amount outstanding				0		0
Revolving Securitization Facility [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity					$ 6,500,000,000
Credit facilities amount outstanding				3,600,000,000
Total Committed Bank Credit Facilities [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				4,400,000,000
Credit facilities amount outstanding				0		$ 0
Committed Bank Credit Facility Expiring 2021 [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				350,000,000
Committed Bank Credit Facility Expiring 2022 [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				1,900,000,000
Committed Bank Credit Facility Expiring 2023 [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				1,800,000,000
Committed Bank Credit Facility Expiring 2024 [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				300,000,000
Three Year Revolving Credit Facility Expiring 2022 [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity				$ 5,000,000,000.0
Credit facility, repayment of principal and accrued interest	$ 3,000,000,000.0
Credit facilities interest rate				1.86%