Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost		$ 96	$ 63	$ 72
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		11,950	10,591	$ 11,409
Pension Benefits | U.S.
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 10,824	$ 9,580
Weighted average expected return on plan assets		5.75%	5.75%	6.00%
Pension Benefits | Non- U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 1,126	$ 1,011
Pension Benefits | Scenario, Forecast | U.S.
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected return on plan assets	5.50%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		1,289	1,324	$ 1,674
Other Postretirement Benefits | U.S.
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 1,247	$ 1,288
Weighted average expected return on plan assets		5.04%	5.11%	5.36%
Expected future discretionary contributions		$ 40
Other Postretirement Benefits | Non- U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		42	$ 36
Other Postretirement Benefits | Scenario, Forecast | U.S.
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected return on plan assets	4.31%
United States Pension Plan of US Entity, Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future discretionary contributions		125
United States Pension Plan of US Entity, Non Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		1,200	$ 1,100
Expected future discretionary contributions		$ 70