Reclassifications from Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	$ 497
Balance ending	(18)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	(38)
Other comprehensive income before reclassifications	0
Amounts reclassified from other comprehensive income	3
Net current-period other comprehensive income	3
Balance ending	(35)
Pension and Other Postretirement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	(24)
Other comprehensive income before reclassifications	0
Amounts reclassified from other comprehensive income	3
Net current-period other comprehensive income	3
Balance ending	(21)
Foreign Currency
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	(14)
Other comprehensive income before reclassifications	0
Amounts reclassified from other comprehensive income	0
Net current-period other comprehensive income	0
Balance ending	$ (14)