Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total revenue from annuity and life insurance contracts recognized		$ 56	$ 56	$ 58
Total investment income (loss) from annuity and life insurance contracts		(448)	1,100	660
Defined Contribution Plan, Cost		63	72	81
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		10,591	11,409	$ 10,741
Estimated net actuarial losses amortized into net periodic benefit cost over the next year		184
Estimated prior service cost amortized into net periodic benefit cost over the next year		(17)
Pension Benefits | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 9,580	$ 10,500
Weighted average expected return on plan assets		5.75%	6.00%	6.00%
Pension Benefits | Non- U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 1,011	$ 909
Pension Benefits | Scenario, Forecast | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected return on plan assets	5.75%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		1,324	1,674	$ 1,759
Estimated net actuarial losses amortized into net periodic benefit cost over the next year		(34)
Estimated prior service cost amortized into net periodic benefit cost over the next year		(11)
Other Postretirement Benefits | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		$ 1,288	$ 1,648
Weighted average expected return on plan assets		5.11%	5.36%	5.53%
Expected future discretionary contributions		$ 50
Other Postretirement Benefits | Non- U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		36	$ 26
Other Postretirement Benefits | Scenario, Forecast | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected return on plan assets	5.11%
United States Pension Plan of US Entity, Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future discretionary contributions		150
United States Pension Plan of US Entity, Non Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations		1,100	$ 1,200
Expected future discretionary contributions		$ 70