Charges and Credits - Summary of Charges and Credits (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Charges And Credits [Line Items]
Charges and credits, Pretax Charge							$ 546	$ 279
Charges and credits, Tax Benefit							53	48
Charges and credits, Noncontrolling Interests							12	20
Charges and credits, Net							$ 481	$ 211
Interest And Other
Charges And Credits [Line Items]
Charges and credits, Pretax Charge				$ 14	$ 15	$ 14
Charges and credits, Tax Benefit				4	4	4
Charges and credits, Noncontrolling Interests				3	3	3
Charges and credits, Net				7	8	7
Interest And Other \| Impairment of Equity Method Investment
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	$ 52	$ 69
Charges and credits, Tax Benefit	4	12
Charges and credits, Net	48	57
Interest And Other \| Workforce reductions
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	57	66	$ 158	65	111
Charges and credits, Tax Benefit	4	3	10	10	17
Charges and credits, Net	53	63	148	55	94
Interest And Other \| Merger and integration-related
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	28	35	49	33	16	11
Charges and credits, Tax Benefit	2	4	1	6	1	2
Charges and credits, Noncontrolling Interests	4	4	4	4	5	2
Charges and credits, Net	22	27	$ 44	$ 23	$ 10	$ 7
Interest And Other \| Gain on Sale of Palliser APS Project
Charges And Credits [Line Items]
Charges and credits, Pretax Charge		(149)
Charges and credits, Tax Benefit		(4)
Charges and credits, Net		$ (145)
Interest And Other \| Amortization of Inventory Fair Value Adjustment
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	66
Charges and credits, Tax Benefit	15
Charges and credits, Net	51
Interest And Other \| Acquisition Related Professional Fees
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	61
Charges and credits, Net	61
Interest And Other \| Acquisition Related Employee Benefits
Charges And Credits [Line Items]
Charges and credits, Pretax Charge	54
Charges and credits, Tax Benefit	2
Charges and credits, Net	$ 52