Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2018

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Pension Cost

Components of net periodic pension cost consisted of the following:

	Three Months Ended
	March 31,
	2018			2017
	(In millions)
Service cost	$	14		$	14
Interest cost		23			26
Expected return on plan assets		(49	)		(41	)
Amortization of unrecognized net actuarial losses		12			17
Curtailment gains		(2	)		—
Pension (benefit) expense	$	(2	)	$	16