Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash dividends (in dollars per share)	$ 2.4600	$ 2.3800	$ 2.3000
Other comprehensive income (loss), net of tax	$ (118)	$ 26	$ (9)
Pension and Other Postretirement Benefit Plans
Other comprehensive income (loss), net of tax	$ (60)
Pension and Other Postretirement Benefit Plans | SCS
Other comprehensive income (loss), net of tax			27
Other comprehensive income (loss), tax			$ 9