Goodwill and Other Intangible Assets - Carrying Value of Goodwill (Detail) - Paper and Packaging [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Goodwill [Line Items]
Balance at beginning of year	$ 35	$ 33
Purchase price accounting adjustment	0	2
Balance at end of period	$ 35	$ 35

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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+ Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details