Restructuring Charges (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 13, 2019	Dec. 31, 2020	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 0	$ 189	$ 206	$ 126
Severance and Other Restructuring Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Translation and Other Adjustment	0	(25)	18	(13)
Restructuring and Related Cost, Incurred Cost	0	152	142	120
Payments for Restructuring	0	120	137	109
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0	53	132	61
Impaired Assets to be Disposed of by Method Other than Sale, Asset Name [Domain]
Restructuring Cost and Reserve [Line Items]
Other Restructuring Costs	$ 0	$ 13	$ 40	$ 2