Equity Activity - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the beginning of the period	$ 4,875	$ 5,423	$ 4,931	$ 5,948
Net transfers from Parent	1,414	145	2,314	786
Other comprehensive income (loss)	(114)	128	(178)	18
Balance at the end of the period	5,481	5,459	5,481	5,459
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the beginning of the period	(1,163)	(1,330)	(1,100)	(1,220)
Net transfers from Parent	(338)		(338)
Other comprehensive income (loss)	(114)	128	(178)	18
Balance at the end of the period	(1,615)	(1,202)	(1,615)	(1,202)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) (net of tax)
Other comprehensive income (loss)	3		3
Balance at the end of the period	3		3
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the beginning of the period			(882)	(1,007)
Other comprehensive income (loss)	(125)	121	(203)	(1)
Balance at the end of the period	(1,084)	(1,007)	(1,084)	(1,007)
Net Change Retirement-Related Benefit Plans
Accumulated Other Comprehensive Income (Loss) (net of tax)
Balance at the beginning of the period			(218)	(214)
Net transfers from Parent			(338)
Other comprehensive income (loss)	8	7	22	19
Balance at the end of the period	$ (534)	$ (195)	$ (534)	$ (195)