Fair Value Measurements (Details1) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Derivatives	$ 22	$ 283
Derivatives	63	12
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Marketable Securities	56	53
Derivatives	22	283
Total Assets at Fair Value	78	336
Derivatives	63	12
Total Liabilities at Fair Value	63	12
Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Marketable Securities	56	53
Derivatives	2	185
Total Assets at Fair Value	58	238
Derivatives	58	0
Total Liabilities at Fair Value	58	0
Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Marketable Securities	0	0
Derivatives	20	98
Total Assets at Fair Value	20	98
Derivatives	5	12
Total Liabilities at Fair Value	5	12
Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Marketable Securities	0	0
Derivatives	0	0
Total Assets at Fair Value	0	0
Derivatives	0	0
Total Liabilities at Fair Value	$ 0	$ 0