Retirement Benefits (Schedule of Total Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. | Pension  Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recognized in net periodic benefit cost and other comprehensive loss	$ 272	$ 160	$ 63
U.S. | Post-retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recognized in net periodic benefit cost and other comprehensive loss	2	2	0
Non-U.S. | Pension  Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recognized in net periodic benefit cost and other comprehensive loss	261	311	(147)
Non-U.S. | Post-retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recognized in net periodic benefit cost and other comprehensive loss	$ 13	$ 5	$ (5)