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Loans Payable, Long-Term Debt and Leases - Narrative (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Debt Instrument [Line Items] |  |  |
Long-term debt, current maturities | $ 2,300,000,000 | $ 2,300,000,000 |
Loans payable and current portion of long-term debt | 2,412,000,000 | 6,431,000,000 |
Long-term debt | 30,690,000,000 | $ 25,360,000,000 |
Face amount of debt | 8,000,000,000 |  |
Long-term debt, maturities, repayments of principal in 2022 | 2,300,000,000 |  |
Long-term debt, maturities, repayments of principal in 2023 | 1,700,000,000 |  |
Long-term debt, maturities, repayments of principal in 2024 | 1,300,000,000 |  |
Long-term debt, maturities, repayments of principal in 2025 | 2,500,000,000 |  |
Long-term debt, maturities, repayments of principal in 2026 | 2,300,000,000 |  |
Long-term debt, interest payments in 2022 | 910,000,000 |  |
Long-term debt, interest payments in 2023 | 875,000,000 |  |
Long-term debt, interest payments in 2024 | 838,000,000 |  |
Long-term debt, interest payments in 2025 | 771,000,000 |  |
Long-term debt, interest payments in 2026 | 743,000,000 |  |
Available borrowing capacity under credit facility | $ 6,000,000,000 |  |
Operating lease, weighted average remaining lease term | 7 years | 8 years |
Operating lease, cost | $ 343,000,000 | $ 340,000,000 | $ 333,000,000
Operating lease, payments | 340,000,000 | 334,000,000 | 275,000,000
Right-of-use asset obtained in exchange for operating lease liability | 117,000,000 | $ 473,000,000 | $ 125,000,000
Lessee, operating lease, lease not yet commenced, amount | $ 86,000,000 |  |
Other Variable Rate Debt |  |  |
Debt Instrument [Line Items] |  |  |
Effective interest rate | 0.00% | 0.45% |
6.30% debentures due 2026 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 135,000,000 | $ 135,000,000 |
Stated interest rate | 6.30% |  |
1.70% notes due 2027 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 1,493,000,000 | 0 |
Stated interest rate | 1.70% |  |
Face amount of debt | $ 1,500,000,000 |  |
1.90% notes due 2028 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 994,000,000 | 0 |
Stated interest rate | 1.90% |  |
Face amount of debt | $ 1,000,000,000 |  |
2.15% notes due 2031 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 1,986,000,000 | 0 |
Stated interest rate | 2.15% |  |
Face amount of debt | $ 2,000,000,000 |  |
2.75% notes due 2051 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 1,979,000,000 | 0 |
Stated interest rate | 2.75% |  |
Face amount of debt | $ 2,000,000,000 |  |
2.90% notes due 2061 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt | $ 1,484,000,000 | 0 |
Stated interest rate | 2.90% |  |
Face amount of debt | $ 1,500,000,000 |  |
Commercial Paper |  |  |
Debt Instrument [Line Items] |  |  |
Loans payable and current portion of long-term debt |  | $ 4,000,000,000 |
Weighted-average interest rate of commercial paper | 0.08% | 0.79% |
Notes Subject To Repayment At Option Of Holder |  |  |
Debt Instrument [Line Items] |  |  |
Loans payable and current portion of long-term debt | $ 149,000,000 | $ 73,000,000 |
Buildings |  |  |
Debt Instrument [Line Items] |  |  |
Operating lease, weighted average remaining lease term | 7 years |  |
Lessee, operating lease, renewal term | 4 years |  |
Vehicles |  |  |
Debt Instrument [Line Items] |  |  |
Operating lease, weighted average remaining lease term | 4 years |  |

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