Nature of Operations and Basis of Presentation - Components of Other (Income) Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other (income) expense, net	$ (6)	$ 8	$ (16)	$ 104
Non-cash pre-tax settlement charge			3	113
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net periodic benefit cost	(9)	(8)	(24)	88
Net loss from investments	3	16	8	16
Other (income) expense, net	$ (6)	$ 8	$ (16)	$ 104