Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	$ 1,387	$ 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	1,387	628
Available-for-sale Debt Securities, Amortized Cost Basis, Current	29	21
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, Current, before Tax	1	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, Current, before Tax	0	0
Debt Securities, Available-for-sale, Current	30	21
Debt Securities, Available-for-sale, Amortized Cost	1,298	1,477
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	111	113
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(43)	(21)
Debt Securities, Available-for-sale	1,366	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	1,306	1,487
Other Investments and Securities, Accumulated Gross Unrealized Gain, Before Tax	112	119
Other Investments and Securities, Accumulated Gross Unrealized Loss, Before Tax	(44)	(22)
Investments, Fair Value Disclosure	1,374	1,584
Cash Equivalents, Marketable Securities and Other Investments, Amortized Cost Basis	2,722	2,136
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Gain, Before Tax	113	119
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Loss, Before Tax	(44)	(22)
Cash Equivalents, Marketable Securities and Other Investments, Fair Value	2,791	2,233
Long-term Debt	(17,045)	(16,410)
Long Term Debt, Accumulated Gross Unrealized Gain, Before Tax	196	7
Long Term Debt, Accumulated Gross Unrealized Loss, Before Tax	(2,792)	(2,258)
Long-term Debt, Fair Value	(19,641)	(18,661)
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	287	168
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(504)	(419)
Derivative Assets (Liabilities), at Fair Value, Net	(217)	(251)
Long Term Debt, Accumulated Fair Value Adjustment	67	1
Derivative, Amount of Hedged Item	2,714	3,490
Interest Rate Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	154	8
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(286)	(283)
Derivative Assets (Liabilities), at Fair Value, Net	(132)	(275)
Foreign Exchange Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	23	101
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(72)	(21)
Derivative Assets (Liabilities), at Fair Value, Net	(49)	80
Commodity Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	110	59
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(146)	(115)
Derivative Assets (Liabilities), at Fair Value, Net	(36)	(56)
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	476	533
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	33
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(15)	(11)
Debt Securities, Available-for-sale	491	555
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	822	944
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	81	80
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(28)	(10)
Debt Securities, Available-for-sale	875	1,014
Held-to-maturity Securities
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	696	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	696	220
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	691	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	$ 691	$ 408