Restructuring, Impairment, and Other Corporate Matters (Restructuring and Other Corporate Matters) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 35	$ 28	$ 371	$ 156
Merger-related costs	10	94	51	94
Other corporate matters	7	0	21	57
Restructuring and other corporate matters	52	122	443	307
Impairment charges	0	0	25	0
Depreciation of abandoned technology	0	0	12	0
Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	30	47	334	145
Exit costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 5	$ (19)	$ 37	$ 11