Debt (Scheduled Remaining Maturity of Long-term Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	$ 4,165
Long-term debt, maturities, repayments of principal in year two	4,536
Long-term debt, maturities, repayments of principal in year three	4,456
Long-term debt, maturities, repayments of principal in year four	1,831
Long-term debt, maturities, repayments of principal in year five	1,916
Long-term debt, maturities, repayments of principal after year five	3,576
Total long-term debt	20,480	$ 17,762
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	2,031
Long-term debt, maturities, repayments of principal in year two	1,412
Long-term debt, maturities, repayments of principal in year three	2,396
Long-term debt, maturities, repayments of principal in year four	25
Long-term debt, maturities, repayments of principal in year five	1,443
Long-term debt, maturities, repayments of principal after year five	3,342
Total long-term debt	10,649	10,037
Secured debt
Debt Instrument [Line Items]
Total long-term debt	9,831	$ 7,725
Long-term debt | Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	2,077
Long-term debt, maturities, repayments of principal in year two	1,480
Long-term debt, maturities, repayments of principal in year three	2,470
Long-term debt, maturities, repayments of principal in year four	107
Long-term debt, maturities, repayments of principal in year five	1,538
Long-term debt, maturities, repayments of principal after year five	3,855
Total long-term debt	11,527
Long-term debt | Secured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	2,134
Long-term debt, maturities, repayments of principal in year two	3,124
Long-term debt, maturities, repayments of principal in year three	2,060
Long-term debt, maturities, repayments of principal in year four	1,806
Long-term debt, maturities, repayments of principal in year five	473
Long-term debt, maturities, repayments of principal after year five	234
Total long-term debt	9,831
Original issue discount | Unsecured debt
Debt Instrument [Line Items]
Debt instrument, unamortized discount	(878)
Original issue discount | Unsecured debt | 2023
Debt Instrument [Line Items]
Debt instrument, unamortized discount, current	(46)
Original issue discount | Unsecured debt | 2024
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(68)
Original issue discount | Unsecured debt | 2025
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(74)
Original issue discount | Unsecured debt | 2026
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(82)
Original issue discount | Unsecured debt | 2027
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	(95)
Original issue discount | Unsecured debt | 2028 and thereafter
Debt Instrument [Line Items]
Debt instrument, unamortized discount, noncurrent	$ (513)