ACQUISITIONS - Narrative (Details) $ / shares in Units, € in Millions, $ in Millions				3 Months Ended		9 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2025 EUR (€)	Jan. 31, 2025 USD ($) plant $ / shares shares	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)
Business Combination [Line Items]
Gain on disposition of business				$ (16)	$ 0	$ 35	$ 0
European Plants | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Combination [Line Items]
Number of plants divested | plant			5
Proceeds from divestiture of businesses	$ 147	€ 125
Gain on disposition of business						51
DS Smith Plc
Business Combination [Line Items]
Number of IP shares issued for each DS Smith share (in shares) | shares			0.1285
Business combination, consideration transferred, equity interest, share issued, number of shares (in shares) | shares			178,126,631
Business combination, voting equity interest acquired, percentage			34.10%
Business combination, price per share (in dollars per share) | $ / shares			$ 55.63
Business combination, consideration transferred			$ 9,900
Business combination, acquisition-related cost, expense				4	26	94	48
Measurement period adjustment, decrease in property, plant, and equipment				89
Measurement period adjustment, increase in contract assets				236
Measurement period adjustment, decrease inventory				212
Business combination, acquiree's revenue since acquisition date, actual				2,200		5,700
Business combination, acquiree's earnings (loss) since acquisition date, actual				(317)		(505)
Business combination, pro forma information, pro forma income (loss), after tax				(1,131)	80	(1,148)	565
DS Smith Plc | Business Combination, Pro Forma Information, Nonrecurring Adjustment, Acquisition-Related Cost
Business Combination [Line Items]
Business combination, pro forma information, pro forma income (loss), after tax				11	11
Business combination, integration-related cost, expense						104	104
DS Smith Plc | Business Combination, Pro Forma Information, Nonrecurring Adjustment, Inventory, Fair Value Adjustment
Business Combination [Line Items]
Business combination, pro forma information, pro forma income (loss), after tax				$ 41		30	30
DS Smith Plc | Additional Amortization Expense on Identifiable Assets
Business Combination [Line Items]
Business combination, pro forma information, pro forma income (loss), after tax					47	16	140
DS Smith Plc | Additional Depreciation Expense on Identifiable Assets
Business Combination [Line Items]
Business combination, pro forma information, pro forma income (loss), after tax					$ 38	$ 13	$ 113