Charges and Credits - Summary of Charges and Credits (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	$ 206
Charges and credits, Tax Benefit	11
Charges and credits, Noncontrolling Interests	4
Charges and credits, Net	191
Interest And Other | Workforce reductions
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	158
Charges and credits, Tax Benefit	10
Charges and credits, Net	148
Interest And Other | Merger and integration-related
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	48	$ 25
Charges and credits, Tax Benefit	1	6
Charges and credits, Noncontrolling Interests	4	5
Charges and credits, Net	$ 43	$ 14