Fair Value Measurement (Fair Value Measurement Inputs) (Details) $ in Millions | 3 Months Ended | 12 Months Ended | | | | |
Mar. 31, 2019USD ($) | Mar. 31, 2018USD ($) | Dec. 31, 2018USD ($)$ / bbl | Dec. 31, 2020USD ($) | Dec. 31, 2019USD ($) | Dec. 31, 2016USD ($)$ / bbl | Nov. 16, 2016USD ($)$ / lb |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Other Assets, Current | $ 560 | | $ 422 | | | | |
Other assets | 2,174 | | 2,172 | | | | |
Proceeds from Sale of Other Assets, contingent consideration | 84 | $ 0 | | | | | |
Assets | 41,059 | $ 36,637 | 42,216 | | | | |
Derivative Liability, Fair Value, Gross Liability | 15 | | 48 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 93 | | 16 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 13 | | 41 | | | | |
Fair Value Measured at Net Asset Value Per Share [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 25 | | 25 | | | | |
Trust Assets Fair Value Disclosure | 57 | | 55 | | | | |
Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 4 | | 4 | | | | |
Trust Assets Fair Value Disclosure | 6 | | 5 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 8 | | 0 | | | | |
Contingent Receivable | 0 | | 0 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 7 | | | | |
Long-term debt, including current portion | 0 | | 0 | | | | |
Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 0 | | 0 | | | | |
Trust Assets Fair Value Disclosure | 123 | | 121 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 174 | | 96 | | | | |
Contingent Receivable | 0 | | 0 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 15 | | 41 | | | | |
Long-term debt, including current portion | 9,659 | | 10,238 | | | | |
Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 0 | | 0 | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | 0 | | | | |
Contingent Receivable | 117 | | 127 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 0 | | | | |
Long-term debt, including current portion | 0 | | 0 | | | | |
Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 29 | | 29 | | | | |
Trust Assets Fair Value Disclosure | 186 | | 181 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 182 | | 96 | | | | |
Contingent Receivable | 117 | | 127 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 15 | | 48 | | | | |
Long-term debt, including current portion | 9,659 | | 10,238 | | | | |
Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Investments, Fair Value Disclosure | 29 | | 29 | | | | |
Trust Assets Fair Value Disclosure | 186 | | 181 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 182 | | 96 | | | | |
Contingent Receivable | 138 | | 143 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 15 | | 48 | | | | |
Long-term debt, including current portion | 9,905 | | 11,141 | | | | |
Embedded Derivative Financial Instruments [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Derivative Liability, Fair Value, Gross Liability | 14 | | 39 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 84 | | 16 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 13 | | 32 | | | | |
Embedded Derivative Financial Instruments [Member] | Level 1 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | 0 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 0 | | | | |
Embedded Derivative Financial Instruments [Member] | Level 2 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 85 | | 23 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 14 | | 39 | | | | |
Embedded Derivative Financial Instruments [Member] | Level 3 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | 0 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 0 | | | | |
Embedded Derivative Financial Instruments [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 85 | | 23 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 14 | | 39 | | | | |
Embedded Derivative Financial Instruments [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 85 | | 23 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 14 | | 39 | | | | |
Forward Contracts [Member] | Level 1 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | | | | | |
Forward Contracts [Member] | Level 2 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 1 | | | | | | |
Forward Contracts [Member] | Level 3 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | | | | | |
Forward Contracts [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 1 | | | | | | |
Forward Contracts [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 1 | | | | | | |
Commodity Contract [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Derivative Liability, Fair Value, Gross Liability | 1 | | 9 | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 9 | | 0 | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 9 | | | | |
Commodity Contract [Member] | Level 1 | | | | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 7 | | | | |
Commodity Contract [Member] | Level 2 | | | | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 1 | | 2 | | | | |
Commodity Contract [Member] | Level 3 | | | | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 0 | | 0 | | | | |
Commodity Contract [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 1 | | 9 | | | | |
Commodity Contract [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Derivatives: [Abstract] | | | | | | | |
Derivative Liability | 1 | | 9 | | | | |
Future [Member] | Level 1 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 8 | | | | | | |
Future [Member] | Level 2 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 1 | | | | | | |
Future [Member] | Level 3 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | | | | | |
Future [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 9 | | | | | | |
Future [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 9 | | | | | | |
Africa and onshore California [Member] | Commodity Contract [Member] | Level 1 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | 0 | | | | |
Africa and onshore California [Member] | Commodity Contract [Member] | Level 2 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 87 | | 73 | | | | |
Africa and onshore California [Member] | Commodity Contract [Member] | Level 3 | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 0 | | 0 | | | | |
Africa and onshore California [Member] | Commodity Contract [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 87 | | 73 | | | | |
Africa and onshore California [Member] | Commodity Contract [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Derivatives: | | | | | | | |
Derivative Asset | 87 | | 73 | | | | |
U.S. core fixed income fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 25 | | 25 | | | | |
Trust Assets Fair Value Disclosure | 57 | | 55 | | | | |
U.S. core fixed income fund [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 0 | | 0 | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
U.S. core fixed income fund [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 0 | | 0 | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
U.S. core fixed income fund [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 0 | | 0 | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
U.S. core fixed income fund [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 25 | | 25 | | | | |
Trust Assets Fair Value Disclosure | 57 | | 55 | | | | |
U.S. core fixed income fund [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 25 | | 25 | | | | |
Trust Assets Fair Value Disclosure | 57 | | 55 | | | | |
Equity securities | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 4 | | 4 | | | | |
Equity securities | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 0 | | 0 | | | | |
Equity securities | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 0 | | 0 | | | | |
Equity securities | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 4 | | 4 | | | | |
Equity securities | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Marketable Securities | 4 | | 4 | | | | |
Government bonds | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Government bonds | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 33 | | 36 | | | | |
Government bonds | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Government bonds | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 33 | | 36 | | | | |
Government bonds | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 33 | | 36 | | | | |
Corporate bonds [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Corporate bonds [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 29 | | 28 | | | | |
Corporate bonds [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Corporate bonds [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 29 | | 28 | | | | |
Corporate bonds [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 29 | | 28 | | | | |
Government mortgage-backed securities [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Government mortgage-backed securities [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 41 | | 38 | | | | |
Government mortgage-backed securities [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Government mortgage-backed securities [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 41 | | 38 | | | | |
Government mortgage-backed securities [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 41 | | 38 | | | | |
Asset-backed securities [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Asset-backed securities [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 12 | | 11 | | | | |
Asset-backed securities [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Asset-backed securities [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 12 | | 11 | | | | |
Asset-backed securities [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 12 | | 11 | | | | |
Money market funds [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 6 | | 5 | | | | |
Money market funds [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Money market funds [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Money market funds [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 6 | | 5 | | | | |
Money market funds [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 6 | | 5 | | | | |
Collateralized Mortgage Backed Securities [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Collateralized Mortgage Backed Securities [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 7 | | 7 | | | | |
Collateralized Mortgage Backed Securities [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Collateralized Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 7 | | 7 | | | | |
Collateralized Mortgage Backed Securities [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 7 | | 7 | | | | |
Municipal bonds [Member] | Level 1 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Municipal bonds [Member] | Level 2 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 1 | | 1 | | | | |
Municipal bonds [Member] | Level 3 | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 0 | | 0 | | | | |
Municipal bonds [Member] | Estimate of Fair Value Measurement [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 1 | | 1 | | | | |
Municipal bonds [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Investment securities (current and long-term): | | | | | | | |
Trust Assets Fair Value Disclosure | 1 | | 1 | | | | |
Bank Time Deposits [Member] | Carrying Amount, Fair Value Disclosure [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Other Assets, Current | 115 | | 109 | | | | |
Other assets | 163 | | 126 | | | | |
Not Designated as Hedging Instrument [Member] | Embedded Derivative Financial Instruments [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Derivative Liability, Fair Value, Gross Liability | 14 | | 39 | | | | |
TF Holdings Limited | Discontinued Operations, Disposed of by Sale | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Other assets | 58 | | 57 | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | | | | | | | $ 120 |
Copper | TF Holdings Limited | Discontinued Operations, Disposed of by Sale | | | | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | | | | | | | 60 |
Cobalt | TF Holdings Limited | Discontinued Operations, Disposed of by Sale | | | | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | | | | | | | $ 60 |
Contingent consideration, reference threshold (in us dollars per pound) | $ / lb | | | | | | | 20 |
Freeport-McMoRan Oil & Gas | Onshore California [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Other Assets, Current | 13 | | | | | | |
Other assets | 16 | | 16 | | | | |
Proceeds from Sale of Other Assets, contingent consideration | 50 | | | | | | |
Assets | 29 | | | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | 150 | | | | | | |
Discontinued Operation, Contingent Receivable, Per Year | | | 50 | | | | |
Freeport-McMoRan Oil & Gas | Deepwater Gulf of Mexico Interests [Member] | | | | | | | |
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items] | | | | | | | |
Other Assets, Current | 19 | | 27 | | | | |
Other assets | $ 119 | | $ 116 | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | | | | | | $ 150 | |
Scenario, Forecast [Member] | Freeport-McMoRan Oil & Gas | Onshore California [Member] | | | | | | | |
Derivatives: | | | | | | | |
Contingent Receivable | | | | $ 50 | $ 50 | | |
Crude Oil [Member] | Freeport-McMoRan Oil & Gas | Onshore California [Member] | | | | | | | |
Derivatives: | | | | | | | |
Contingent consideration, reference threshold (in us dollars per pound) | $ / bbl | | | 70 | | | 70 | |
Maximum [Member] | Copper | TF Holdings Limited | Discontinued Operations, Disposed of by Sale | | | | | | | |
Derivatives: | | | | | | | |
Contingent consideration, reference threshold (in us dollars per pound) | $ / lb | | | | | | | 3.50 |