Condensed Consolidated Statements Of Financial Position (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 1	$ 3
Accumulated depreciation	1,975	1,961
Accumulated amortization	$ 625	$ 599
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	53,300,000	53,200,000
Common stock, shares outstanding (in shares)	40,500,000	40,800,000