Business Segments (Corporate Items) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenues - divested business	$ 1,353	$ 1,039
Expenses:
Amortization expense of acquired intangible assets	25	26
Merger and strategic initiatives expense	7	9
Restructuring charges	12	0
Extinguishment of debt	36	0
Operating income	275	275
Corporate Items
Segment Reporting Information [Line Items]
Revenues - divested business	0	10
Expenses:
Amortization expense of acquired intangible assets	25	26
Merger and strategic initiatives expense	7	9
Restructuring charges	12	0
Extinguishment of debt	36	0
Expenses - divested business	0	8
Other	10	2
Total expenses	90	45
Operating income	$ (90)	$ (35)