Debt (Scheduled Remaining Maturity of Long-term Debt) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	$ 2,900
Long-term debt, maturities, repayments of principal in year two	4,525
Long-term debt, maturities, repayments of principal in year three	4,473
Long-term debt, maturities, repayments of principal in year four	1,873
Long-term debt, maturities, repayments of principal in year five	1,881
Long-term debt, maturities, repayments of principal after year five	4,489
Total long-term debt	20,141	$ 17,762
Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	1,227
Long-term debt, maturities, repayments of principal in year two	1,411
Long-term debt, maturities, repayments of principal in year three	2,412
Long-term debt, maturities, repayments of principal in year four	59
Long-term debt, maturities, repayments of principal in year five	1,442
Long-term debt, maturities, repayments of principal after year five	4,217
Total long-term debt	10,768	10,037
Secured debt
Debt Instrument [Line Items]
Total long-term debt	9,373	$ 7,725
Long-term debt | Unsecured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	1,258
Long-term debt, maturities, repayments of principal in year two	1,479
Long-term debt, maturities, repayments of principal in year three	2,486
Long-term debt, maturities, repayments of principal in year four	141
Long-term debt, maturities, repayments of principal in year five	1,537
Long-term debt, maturities, repayments of principal after year five	4,730
Total long-term debt	11,631
Long-term debt | Secured debt
Debt Instrument [Line Items]
Long-term debt, maturities, repayments of principal in next 12 months	1,673
Long-term debt, maturities, repayments of principal in year two	3,114
Long-term debt, maturities, repayments of principal in year three	2,061
Long-term debt, maturities, repayments of principal in year four	1,814
Long-term debt, maturities, repayments of principal in year five	439
Long-term debt, maturities, repayments of principal after year five	272
Total long-term debt	9,373
Original issue discount | Unsecured debt
Debt Instrument [Line Items]
Debt instrument, unamortized discount	(863)
Original issue discount | Unsecured debt | 2023
Debt Instrument [Line Items]
Debt instrument, unamortized discount, current	(31)
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)