Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	$ 1,806	$ 628
Cash Equivalents, Accumulated Gross Unrealized Gain, Before Tax	0	0
Cash Equivalents, Accumulated Gross Unrealized Loss, Before Tax	0	0
Cash Equivalents, Fair Value	1,806	628
Available-for-sale Debt Securities, Amortized Cost Basis, Current	1	21
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, Current, before Tax	0	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, Current, before Tax	0	0
Debt Securities, Available-for-sale, Current	1	21
Debt Securities, Available-for-sale, Amortized Cost	1,335	1,477
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	80	113
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(117)	(21)
Debt Securities, Available-for-sale	1,298	1,569
Equity Securities, Amortized Cost Basis	8	10
Equity Securities, Accumulated Gross Unrealized Gain, Before Tax	1	6
Equity Securities, Accumulated Gross Unrealized Loss, Before Tax	(1)	(1)
Equity Securities, Fair Value	8	15
Other Investments and Securities, at Cost	1,343	1,487
Other Investments and Securities, Accumulated Gross Unrealized Gain, Before Tax	81	119
Other Investments and Securities, Accumulated Gross Unrealized Loss, Before Tax	(118)	(22)
Investments, Fair Value Disclosure	1,306	1,584
Cash Equivalents, Marketable Securities and Other Investments, Amortized Cost Basis	3,150	2,136
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Gain, Before Tax	81	119
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Loss, Before Tax	(118)	(22)
Cash Equivalents, Marketable Securities and Other Investments, Fair Value	3,113	2,233
Long-term Debt	(16,697)	(16,410)
Long Term Debt, Accumulated Gross Unrealized Gain, Before Tax	384	7
Long Term Debt, Accumulated Gross Unrealized Loss, Before Tax	(1,326)	(2,258)
Long-term Debt, Fair Value	(17,639)	(18,661)
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	380	168
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(656)	(419)
Derivative Assets (Liabilities), at Fair Value, Net	(276)	(251)
Long Term Debt, Accumulated Fair Value Adjustment	68	1
Derivative, Amount of Hedged Item	2,790	3,490
Interest Rate Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	194	8
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(331)	(283)
Derivative Assets (Liabilities), at Fair Value, Net	(137)	(275)
Foreign Exchange Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	53	101
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(39)	(21)
Derivative Assets (Liabilities), at Fair Value, Net	14	80
Commodity Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	133	59
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(286)	(115)
Derivative Assets (Liabilities), at Fair Value, Net	(153)	(56)
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	458	533
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	37	33
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(33)	(11)
Debt Securities, Available-for-sale	462	555
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	877	944
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	43	80
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(84)	(10)
Debt Securities, Available-for-sale	836	1,014
Held-to-maturity Securities
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	1,233	220
Cash Equivalents, Accumulated Gross Unrealized Gain, Before Tax	0	0
Cash Equivalents, Accumulated Gross Unrealized Loss, Before Tax	0	0
Cash Equivalents, Fair Value	1,233	220
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	573	408
Cash Equivalents, Accumulated Gross Unrealized Gain, Before Tax	0	0
Cash Equivalents, Accumulated Gross Unrealized Loss, Before Tax	0	0
Cash Equivalents, Fair Value	$ 573	$ 408