Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	$ 816	$ 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	816	628
Available-for-sale Debt Securities, Amortized Cost Basis, Current	2	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	2	21
Debt Securities, Available-for-sale, Amortized Cost	1,388	1,477
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	115	113
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(54)	(21)
Debt Securities, Available-for-sale	1,449	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	1,396	1,487
Other Investments and Securities, Accumulated Gross Unrealized Gain, Before Tax	116	119
Other Investments and Securities, Accumulated Gross Unrealized Loss, Before Tax	(55)	(22)
Investments, Fair Value Disclosure	1,457	1,584
Cash Equivalents, Marketable Securities and Other Investments, Amortized Cost Basis	2,214	2,136
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Gain, Before Tax	116	119
Cash Equivalents, Marketable Securities and Other Investments, Accumulated Gross Unrealized Loss, Before Tax	(55)	(22)
Cash Equivalents, Marketable Securities and Other Investments, Fair Value	2,275	2,233
Long-term Debt	(16,739)	(16,410)
Long Term Debt, Accumulated Gross Unrealized Gain, Before Tax	182	7
Long Term Debt, Accumulated Gross Unrealized Loss, Before Tax	(2,560)	(2,258)
Long-term Debt, Fair Value	(19,117)	(18,661)
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	338	168
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(550)	(419)
Derivative Assets (Liabilities), at Fair Value, Net	(212)	(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	190	8
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(323)	(283)
Derivative Assets (Liabilities), at Fair Value, Net	(133)	(275)
Foreign Exchange Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	43	101
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(26)	(21)
Derivative Assets (Liabilities), at Fair Value, Net	17	80
Commodity Contract [Member]
Debt Securities, Available-for-sale [Line Items]
Derivative Assets (Liabilities), Accumulated Gross Unrealized Gain, Before Tax	105	59
Derivative Assets (Liabilities), Accumulated Gross Unrealized Loss, Before Tax	(201)	(115)
Derivative Assets (Liabilities), at Fair Value, Net	(96)	(56)
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	506	533
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	28	33
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(19)	(11)
Debt Securities, Available-for-sale	515	555
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	882	944
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	87	80
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(35)	(10)
Debt Securities, Available-for-sale	934	1,014
Held-to-maturity Securities
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	297	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	297	220
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, at Carrying Value	519	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	$ 519	$ 408