Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019
Income Taxes
Provision for income taxes	$ 576	$ 471	$ 776
Undistributed earnings of foreign subsidiaries expected to be repatriated	103	102
Undistributed earnings of foreign subsidiaries	7,700
Operating Loss Carryforwards, Valuation Allowance	860
Income tax loss carryforwards, subject to expiration	457
Remaining amount of loss carryforwards that has no expiration date	403
Unrecognized tax benefits that would reduce our effective tax rate if recognized	326
Total accrued penalties and net accrued interest	16	20
Aggregate resolution of uncertainties	180
U.S. Tax Cuts and Jobs Act
Income Taxes
Net Expense for U.S. Tax Cuts and Jobs Act		36
Provision for income taxes		$ 81
Undistributed earnings of foreign subsidiaries expected to be repatriated	900
Undistributed earnings of foreign subsidiaries	5,600
Undistributed earnings of foreign subsidiaries considered indefinitely reinvested	$ 4,700
Brazil Tax Matter [Member]
Income Taxes
Proposed Tax Adjustments and Penalties, Foreign Tax Authority				$ 90