Retirement Plans - Schedule Of Components Of Net Periodic Benefit Cost (Details) - Pension Plan - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of net periodic benefit cost
Interest cost	$ 4	$ 6	$ 12	$ 17
Expected return on plan assets	(7)	(7)	(15)	(19)
Actuarial (gain) loss	2	3	6	10
Other			2	0
Net periodic benefit cost	$ (1)	$ 2	$ 5	$ 8