Earnings Per Share Attributable To International Paper Company Common Shareholders (Reconciliation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2016	[2]	Sep. 30, 2016	[2]	Jun. 30, 2016	[2]	Mar. 31, 2016	[2]	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Earnings Per Share, Basic and Diluted [Line Items]
Earnings (loss) from continuing operations																	$ 2,110		$ 802		$ 853
Weighted average common shares outstanding																	412.7		411.1		417.4
Weighted average common shares outstanding – assuming dilution																	417.7		415.6		420.6
Basic earnings (loss) per share from continuing operations	$ 3.56		$ 0.89		$ 0.20		$ 0.47		$ 0.47		$ 0.68		$ 0.00		$ 0.80		$ 5.11	[1]	$ 1.95	[2]	$ 2.05
Diluted earnings (loss) per share from continuing operations	$ 3.52		$ 0.88		$ 0.20		$ 0.46		$ 0.47		$ 0.67		$ 0.00		$ 0.80		$ 5.05	[1]	$ 1.93	[2]	$ 2.03
Restricted performance share plan
Earnings Per Share, Basic and Diluted [Line Items]
Effect of dilutive securities:																	5.0		4.5		3.2

[1] 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

[2] Includes the following pre-tax charges (gains): 2016In millions Q1 Q2 Q3 Q4Riegelwood mill conversion costs $9 $— $— $—India Packaging evaluation write-off — — 17 —Early debt extinguishment costs — — 29 —Write-off of certain regulatory pre-engineering costs — — 8 —Costs associated with the newly acquired pulp business — 5 7 19Asia Box impairment / restructuring 37 28 5 —Gain on sale of investment in Arizona Chemical (8) — — —Turkey mill closure — — — 7Amortization of Weyerhaeuser inventory fair value step-up — — — 19Non-operating pension expense 44 487 42 37Total $82 $520 $108 $82