Income Taxes (Schedule of Income Before Income Tax, Domestic and Foreign) (Detail) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	[2]	Sep. 30, 2017	[2]	Jun. 30, 2017	[2]	Mar. 31, 2017	[2]	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S.																	$ 1,450		$ 297		$ 411
Non-U.S.																	331		551		384
EARNINGS (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES AND EQUITY EARNINGS (LOSSES)	$ 382		$ 553		$ 490		$ 356		$ 197		$ 457		$ (23)		$ 217		$ 1,781	[1]	$ 848	[2]	$ 795

[1] Includes the following pre-tax charges (gains): 2018In millions Q1 Q2 Q3 Q4Smurfit-Kappa acquisition proposal costs $— $12 $— $—Legal settlement 9 — — —Litigation settlement recovery — — — (5)Environmental remediation reserve adjustment — — 9 —EMEA Packaging optimization 22 26 — (1)Abandoned property removal 9 9 6 8Riverdale mill conversion costs — — 5 4Brazil Packaging impairment — — 122 —Debt extinguishment costs — — — 10Gain on sale of investment in Liaison Technologies — — — (31)Non-operating pension expense 4 36 25 429Total $44 $83 $167 $414

[2] Includes the following pre-tax charges (gains): 2017In millions Q1 Q2 Q3 Q4Gain on sale of investment in ArborGen $— $(14) $— $—Costs associated with the pulp business acquired in 2016 4 5 6 18Amortization of Weyerhaeuser inventory fair value step-up 14 — — —Holmen bargain purchase gain (6) — — —Abandoned property removal 2 5 7 6Kleen Products settlement — 354 — —Asia Foodservice sale — 9 — —Brazil Packaging wood supply accelerated amortization — — 10 —Debt extinguishment costs — — — 83Interest income on income tax refund claims — (4) — (1)Other items — (2) — —Non-operating pension expense 31 34 33 386Total $45 $387 $56 $492