Fair Value Measurement - Fair Value Measurement Inputs (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2016
Investment securities (current and long-term):
Marketable Securities	$ 0
Other Assets, Current	529	$ 523
Other assets	1,445	1,460
Derivatives:
Derivative Asset	191	73
Derivatives: [Abstract]
Derivative Liability	18	24
Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Investments, Fair Value Disclosure	28	29
Trust Assets Fair Value Disclosure	62	64
Derivatives:
Derivative Asset	0	0
Discontinued Operation, Contingent Receivable	0	0
Derivatives: [Abstract]
Derivative Liability	0	0
Long-term debt, including current portion	0	0
Level 1
Investment securities (current and long-term):
Investments, Fair Value Disclosure	70	50
Trust Assets Fair Value Disclosure	8	8
Derivatives:
Derivative Asset	19	10
Discontinued Operation, Contingent Receivable	0	0
Derivatives: [Abstract]
Derivative Liability	1	1
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	128	137
Derivatives:
Derivative Asset	176	67
Discontinued Operation, Contingent Receivable	0	0
Derivatives: [Abstract]
Derivative Liability	21	27
Long-term debt, including current portion	10,190	10,630
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
Discontinued Operation, Contingent Receivable	74	81
Derivatives: [Abstract]
Derivative Liability	0	0
Long-term debt, including current portion	0	0
Estimate of Fair Value Measurement
Investment securities (current and long-term):
Investments, Fair Value Disclosure	98	79
Trust Assets Fair Value Disclosure	198	209
Derivatives:
Derivative Asset	195	77
Discontinued Operation, Contingent Receivable	74	81
Derivatives: [Abstract]
Derivative Liability	22	28
Long-term debt, including current portion	10,190	10,630
Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Investments, Fair Value Disclosure	98	79
Trust Assets Fair Value Disclosure	198	209
Derivatives:
Derivative Asset	195	77
Discontinued Operation, Contingent Receivable	84	90
Derivatives: [Abstract]
Derivative Liability	22	28
Long-term debt, including current portion	9,621	9,450
Embedded Derivative Financial Instruments
Derivatives:
Derivative Asset	167	61
Derivatives: [Abstract]
Derivative Liability	18	24
Embedded Derivative Financial Instruments | Fair Value Measured at Net Asset Value Per Share
Derivatives:
Derivative Asset	0	0
Derivatives: [Abstract]
Derivative Liability	0	0
Embedded Derivative Financial Instruments | Level 1
Derivatives:
Derivative Asset	0	0
Derivatives: [Abstract]
Derivative Liability	0	0
Embedded Derivative Financial Instruments | Level 2
Derivatives:
Derivative Asset	169	64
Derivatives: [Abstract]
Derivative Liability	20	27
Embedded Derivative Financial Instruments | Level 3
Derivatives:
Derivative Asset	0	0
Derivatives: [Abstract]
Derivative Liability	0	0
Embedded Derivative Financial Instruments | Estimate of Fair Value Measurement
Derivatives:
Derivative Asset	169	64
Derivatives: [Abstract]
Derivative Liability	20	27
Embedded Derivative Financial Instruments | Carrying Amount, Fair Value Disclosure
Derivatives:
Derivative Asset	169	64
Derivatives: [Abstract]
Derivative Liability	20	27
Forward Contracts | Level 1
Derivatives:
Derivative Asset	1	1
Forward Contracts | Level 2
Derivatives:
Derivative Asset	1	0
Forward Contracts | Level 3
Derivatives:
Derivative Asset	0	0
Forward Contracts | Estimate of Fair Value Measurement
Derivatives:
Derivative Asset	2	1
Forward Contracts | Carrying Amount, Fair Value Disclosure
Derivatives:
Derivative Asset	2	1
Commodity Contract
Derivatives:
Derivative Asset	24	12
Derivatives: [Abstract]
Derivative Liability	0	0
Commodity Contract | Fair Value Measured at Net Asset Value Per Share
Derivatives:
Derivative Asset	0	0
Commodity Contract | Fair Value Measured at Net Asset Value Per Share | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	0	0
Commodity Contract | Level 1
Derivatives:
Derivative Asset		9
Commodity Contract | Level 1 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	1	1
Commodity Contract | Level 2
Derivatives:
Derivative Asset		3
Commodity Contract | Level 2 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	1	0
Commodity Contract | Level 3
Derivatives:
Derivative Asset		0
Commodity Contract | Level 3 | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	0	0
Commodity Contract | Estimate of Fair Value Measurement
Derivatives:
Derivative Asset		12
Commodity Contract | Estimate of Fair Value Measurement | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	2	1
Commodity Contract | Carrying Amount, Fair Value Disclosure
Derivatives:
Derivative Asset		12
Commodity Contract | Carrying Amount, Fair Value Disclosure | Forward Contracts
Derivatives: [Abstract]
Derivative Liability	2	1
Future | Level 1
Derivatives:
Derivative Asset	18
Future | Level 2
Derivatives:
Derivative Asset	6
Future | Level 3
Derivatives:
Derivative Asset	0
Future | Estimate of Fair Value Measurement
Derivatives:
Derivative Asset	24
Future | Carrying Amount, Fair Value Disclosure
Derivatives:
Derivative Asset	24
U.S. core fixed income fund | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Marketable Securities	28	29
Trust Assets Fair Value Disclosure	62	64
U.S. core fixed income fund | 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 | 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 | 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 | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Marketable Securities	28	29
Trust Assets Fair Value Disclosure	62	64
U.S. core fixed income fund | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Marketable Securities	28	29
Trust Assets Fair Value Disclosure	62	64
Equity securities | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Marketable Securities		0
Equity securities | Level 1
Investment securities (current and long-term):
Marketable Securities	70	50
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
Investment securities (current and long-term):
Marketable Securities	70	50
Equity securities | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Marketable Securities	70	50
Government bonds | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
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	49	53
Government bonds | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Government bonds | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	49	53
Government bonds | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	49	53
Corporate bonds | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Corporate bonds | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Corporate bonds | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	40	45
Corporate bonds | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Corporate bonds | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	40	45
Corporate bonds | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	40	45
Government mortgage-backed securities | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Government mortgage-backed securities | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Government mortgage-backed securities | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	23	20
Government mortgage-backed securities | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Government mortgage-backed securities | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	23	20
Government mortgage-backed securities | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	23	20
Asset-backed securities | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Asset-backed securities | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Asset-backed securities | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	13	18
Asset-backed securities | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Asset-backed securities | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	13	18
Asset-backed securities | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	13	18
Money market funds | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Money market funds | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	8	8
Money market funds | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Money market funds | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0	0
Money market funds | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	8	8
Money market funds | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	8	8
Collateralized Mortgage Backed Securities | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0
Collateralized Mortgage Backed Securities | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0
Collateralized Mortgage Backed Securities | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	3
Collateralized Mortgage Backed Securities | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	0
Collateralized Mortgage Backed Securities | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	3
Collateralized Mortgage Backed Securities | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure	3
Municipal bonds | Fair Value Measured at Net Asset Value Per Share
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		0
Municipal bonds | Level 1
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		0
Municipal bonds | Level 2
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		1
Municipal bonds | Level 3
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		0
Municipal bonds | Estimate of Fair Value Measurement
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		1
Municipal bonds | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Trust Assets Fair Value Disclosure		1
Bank Time Deposits | Carrying Amount, Fair Value Disclosure
Investment securities (current and long-term):
Other Assets, Current	117	114
Other assets	133	132
Fair Value, Recurring [Member] | Forward Contracts | Estimate of Fair Value Measurement
Derivatives:
Derivative Asset	0	0
Deepwater Gulf of Mexico Interests | Freeport-McMoRan Oil & Gas
Investment securities (current and long-term):
Other Assets, Current	20	20
Other assets	$ 64	$ 70
Derivatives:
Discontinued Operation, Contingent Receivable			$ 150