Debt (Details) - USD ($)	Jun. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Total short-term debt	$ 17,039,000,000	$ 17,413,000,000
Unamortized discount	(21,000,000)	(18,000,000)
Unamortized debt issuance costs	(235,000,000)	(235,000,000)
Fair value adjustments	(331,000,000)	(1,044,000,000)
Total long-term debt	120,355,000,000	120,455,000,000
Total debt	$ 137,394,000,000	$ 137,868,000,000
Average Contractual (interest rate)	4.70%	4.80%
Average Effective (interest rate)	4.70%	4.80%
Debt Carrying Value Fair Value	$ 41,800,000,000	$ 41,100,000,000
Fair value of short-term debt	15,900,000,000	16,200,000,000
Discontinued Hedged Debt	(411,000,000)	(450,000,000)
Floating Rate Demand Notes [Member]
Debt Instrument [Line Items]
Total short-term debt	12,428,000,000	12,040,000,000
Other short-term debt [Member]
Debt Instrument [Line Items]
Total short-term debt	3,462,000,000	4,173,000,000
Asset-backed Securities [Member]
Debt Instrument [Line Items]
Total short-term debt	1,149,000,000	1,200,000,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Notes payable within one year	14,362,000,000	12,871,000,000
Notes payable after one year	52,005,000,000	49,607,000,000
Asset-backed Securities [Member]
Debt Instrument [Line Items]
Notes payable within one year	21,960,000,000	23,050,000,000
Notes payable after one year	$ 32,615,000,000	$ 36,224,000,000
Total short-term debt [Member]
Debt Instrument [Line Items]
Average Contractual (interest rate)	4.20%	4.70%
Average Effective (interest rate)	4.20%	4.70%
Total long-term debt [Member]
Debt Instrument [Line Items]
Average Contractual (interest rate)	4.70%	4.80%
Average Effective (interest rate)	4.80%	4.80%
Fair Value, Nonrecurring [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Fair value of debt	$ 139,148,000,000	$ 140,046,000,000