Income Taxes, Details of the Tax Reform Adjustment (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended		24 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Details of the Tax Reform Adjustment
Income tax benefit from the remeasurement of U.S. deferred income tax assets and liabilities, accounting complete			$ (2,643)	$ (2,643)
Tax on the deemed repatriation of the accumulated earnings and profits of our international subsidiaries, provisional			734
Tax on the deemed repatriation of the accumulated earnings and profits of our international subsidiaries, measurement period adjustment	$ 6	$ 6
Tax on the deemed repatriation of the accumulated earnings and profits of our international subsidiaries, accounting complete				740
Recognition of foreign withholding tax, net of U.S. federal tax benefit, accounting complete			47	47
Deductibility of certain executive compensation expense, incomplete accounting			0
Deductibility of certain executive compensation expense, measurement period adjustment		5
Deductibility of certain executive compensation expense, accounting complete				5
Income tax expense associated with the statutory income tax rate differential on accrual to return adjustments that were identified upon completion of our U.S. federal income tax return in 2018, incomplete accounting			0
Income tax expense associated with the statutory income tax rate differential on accrual to return adjustments that were identified upon completion of our U.S. federal income tax return in 2018, measurement period adjustment		9
Income tax expense associated with the statutory income tax rate differential on accrual to return adjustments that were identified upon completion of our U.S. federal income tax return in 2018, accounting complete				9
Foreign tax credit available to offset the tax on deemed repatriation of the accumulated earnings and profits of our international subsidiaries, incomplete accounting			0
Foreign tax credit available to offset the tax on deemed repatriation of the accumulated earnings and profits of our international subsidiaries, measurement period adjustment	$ (32)	(32)
Foreign tax credit available to offset the tax on deemed repatriation of the accumulated earnings and profits of our international subsidiaries, accounting complete				(32)
Tax Reform benefit, incomplete accounting			$ (1,862)
Tax Reform benefit, measurement period adjustment		$ (12)
Tax Reform benefit, accounting complete				$ (1,874)