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Derivatives and Fair Value of Financial Instruments - Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Trading securities	$ 1,465	$ 1,434
Investments
Amount invested	47	38	$ 21
Commodities
Assets:
Margin account	15	13
Financial services company
Investments
Amount invested	30
Domestic equity securities
Assets:
Trading securities	702	706
Domestic debt securities
Assets:
Trading securities	496	460
Foreign equity securities
Assets:
Trading securities	133	189
Foreign debt securities
Assets:
Trading securities	68	48
Money market funds held in trading accounts
Assets:
Trading securities	47	12
Recurring basis \| Level 1
Assets:
Total assets	1,134	1,095
Liabilities:
Total liabilities	19	4
Recurring basis \| Level 1 \| Commodities
Assets:
Derivatives	28	6
Liabilities:
Derivatives	19	4
Recurring basis \| Level 1 \| Domestic equity securities \| Short-term investments
Assets:
Trading securities	702	706
Recurring basis \| Level 1 \| Domestic equity securities \| Other current assets
Assets:
Trading securities	14	40
Recurring basis \| Level 1 \| Domestic debt securities \| Short-term investments
Assets:
Trading securities	196	127
Recurring basis \| Level 1 \| Foreign equity securities \| Short-term investments
Assets:
Trading securities	133	189
Recurring basis \| Level 1 \| Foreign equity securities \| Other current assets
Assets:
Trading securities	3	3
Recurring basis \| Level 1 \| Money market funds held in trading accounts \| Short-term investments
Assets:
Trading securities	47	12
Recurring basis \| Level 1 \| Money market funds held in trading accounts \| Other current assets
Assets:
Trading securities	6	6
Recurring basis \| Level 1 \| Other trading investments \| Short-term investments
Assets:
Trading securities	3	4
Recurring basis \| Level 1 \| Fixed income securities \| Other current assets
Assets:
Trading securities	2	2
Recurring basis \| Level 2
Assets:
Total assets	387	396
Liabilities:
Total liabilities	10	3
Recurring basis \| Level 2 \| Interest rate swaps
Assets:
Derivatives	1
Recurring basis \| Level 2 \| Foreign currencies
Liabilities:
Derivatives	9	3
Recurring basis \| Level 2 \| Domestic debt securities \| Short-term investments
Assets:
Trading securities	300	333
Recurring basis \| Level 2 \| Foreign debt securities \| Short-term investments
Assets:
Trading securities	68	48
Recurring basis \| Level 2 \| Other trading investments \| Short-term investments
Assets:
Trading securities	17	15
Liabilities:
Derivatives	1
Recurring basis \| Level 2 \| Fixed income securities \| Other current assets
Assets:
Trading securities	1
Recurring basis \| Level 3
Assets:
Total assets	31
Liabilities:
Contingent consideration	16	13
Total liabilities	16	13
Recurring basis \| Level 3 \| Long-term investments
Assets:
Long term investments	31
Recurring basis \| Fair Value
Assets:
Total assets	1,552	1,491
Liabilities:
Contingent consideration	16	13
Total liabilities	45	20
Recurring basis \| Fair Value \| Commodities
Assets:
Derivatives	28	6
Liabilities:
Derivatives	19	4
Recurring basis \| Fair Value \| Interest rate swaps
Assets:
Derivatives	1
Recurring basis \| Fair Value \| Foreign currencies
Liabilities:
Derivatives	9	3
Recurring basis \| Fair Value \| Long-term investments
Assets:
Long term investments	31
Recurring basis \| Fair Value \| Domestic equity securities \| Short-term investments
Assets:
Trading securities	702	706
Recurring basis \| Fair Value \| Domestic equity securities \| Other current assets
Assets:
Trading securities	14	40
Recurring basis \| Fair Value \| Domestic debt securities \| Short-term investments
Assets:
Trading securities	496	460
Recurring basis \| Fair Value \| Foreign equity securities \| Short-term investments
Assets:
Trading securities	133	189
Recurring basis \| Fair Value \| Foreign equity securities \| Other current assets
Assets:
Trading securities	3	3
Recurring basis \| Fair Value \| Foreign debt securities \| Short-term investments
Assets:
Trading securities	68	48
Recurring basis \| Fair Value \| Money market funds held in trading accounts \| Short-term investments
Assets:
Trading securities	47	12
Recurring basis \| Fair Value \| Money market funds held in trading accounts \| Other current assets
Assets:
Trading securities	6	6
Recurring basis \| Fair Value \| Other trading investments \| Short-term investments
Assets:
Trading securities	20	19
Liabilities:
Derivatives	1
Recurring basis \| Fair Value \| Fixed income securities \| Other current assets
Assets:
Trading securities	$ 3	$ 2