Derivative and Financial Instruments - Financial Instruments Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Remaining maturities within one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, carried at fair value	$ 13	$ 9
Short Term Investments At Fair Value	289	99
Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	216	133
Corporate Debt [Member] | Remaining maturities within one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, carried at fair value	0	1
Short Term Investments At Fair Value	130	59
Corporate Debt [Member] | Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	143	99
Commercial Paper [Member] | Remaining maturities within one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, carried at fair value	13	8
Short Term Investments At Fair Value	155	30
US Government Debt Securities [Member] | Remaining maturities within one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, carried at fair value	0	0
Short Term Investments At Fair Value	4	10
US Government Debt Securities [Member] | Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	13	15
US Government Agencies Obligations [Member] | Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	17	0
Foreign Government Debt [Member] | Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	2	0
Asset-backed Securities [Member] | Remaining maturities within one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Short Term Investments At Fair Value	0	0
Asset-backed Securities [Member] | Remaining maturities greater than one year through five years [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments and Long Term Receivable Carried At Fair Value	$ 41	$ 19