Pension And Other Retirement Benefits - Summary of Pre-Tax Net Actuarial Losses and Prior Service Cost Recognized in Accumulated Other Comprehensive Income (Loss) (Detail) - U.S. Plans - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pension Plans
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Net actuarial losses	$ (116)	$ (96)
Net prior service costs	4	4
Total recognized in AOCI – pretax	(112)	(92)
Other Retirement Plans
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Net actuarial losses	(6)	0
Net prior service costs	0	0
Total recognized in AOCI – pretax	$ (6)	$ 0