Employee Benefit Plans (Net Periodic Benefit Costs) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 8	$ 12
Interest cost	27	16	14
Amortization of prior service credit	(7)	(11)	(54)
Amortization of actuarial losses/(gains)	(1)	12	20
Settlements, curtailments, and special termination benefits	2
Net periodic benefit cost/(income)	21	25	(8)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	9	9
Interest cost	111	73	65
Expected return on plan assets	110	140	152
Amortization of prior service credit	0
Amortization of actuarial losses/(gains)	21	34	39
Settlements, curtailments, and special termination benefits	192	6	53
Net periodic benefit cost/(income)	$ 221	$ (18)	$ 14