Interim Financial Results (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 5,711		$ 5,517		$ 5,383		$ 5,132		$ 5,000		$ 4,864		$ 4,914		$ 4,717		$ 21,743	[1]	$ 19,495	[1]	$ 20,675	[1]
Earnings (loss) from continuing operations before income taxes and equity earnings	197	[2]	457	[2]	(23)	[2]	217	[2]	244	[3]	320	[3]	(76)	[3]	307	[3]	848	[2]	795	[3]	1,132
Gain (loss) from discontinued operations	(8)	[4]	29	[4]	(4)	[4]	17	[4]	24	[5]	34	[5]	40	[5]	4	[5]	34	[4]	102	[5]	85
Net earnings (loss) attributable to International Paper Company	$ 1,460	[2],[4],[6]	$ 395	[2],[4],[6]	$ 80	[2],[4],[6]	$ 209	[2],[4],[6]	$ 218	[3],[5],[7]	$ 312	[3],[5],[7]	$ 40	[3],[5],[7]	$ 334	[3],[5],[7]	$ 2,144	[2],[4],[6]	$ 904	[3],[5],[7]	$ 938
Earnings (loss) from continuing operations	$ 3.56	[2]	$ 0.89	[2]	$ 0.20	[2]	$ 0.47	[2]	$ 0.47	[3]	$ 0.68	[3]	$ 0.00	[3]	$ 0.80	[3]	$ 5.11	[2]	$ 1.95	[3]	$ 2.05
Gain (loss) from discontinued operations	(0.02)	[4]	0.07	[4]	(0.01)	[4]	0.04	[4]	0.06	[5]	0.08	[5]	0.10	[5]	0.01	[5]	0.08	[4]	0.25	[5]	0.20
Net earnings (loss)	3.54	[2],[4],[6]	0.96	[2],[4],[6]	0.19	[2],[4],[6]	0.51	[2],[4],[6]	0.53	[3],[5],[7]	0.76	[3],[5],[7]	0.10	[3],[5],[7]	0.81	[3],[5],[7]	5.19	[2],[4],[6]	2.20	[3],[5],[7]	2.25
Diluted earnings (loss) per share from continuing operations	3.52	[2]	0.88	[2]	0.20	[2]	0.46	[2]	0.47	[3]	0.67	[3]	0.00	[3]	0.80	[3]	5.05	[2]	1.93	[3]	2.03
Gain (loss) from discontinued operations	(0.02)	[4]	0.07	[4]	(0.01)	[4]	0.04	[4]	0.06	[5]	0.08	[5]	0.10	[5]	0.01	[5]	0.08	[4]	0.25	[5]	0.20
Net earnings (loss)	3.50	[2],[4],[6]	0.95	[2],[4],[6]	0.19	[2],[4],[6]	0.50	[2],[4],[6]	0.53	[3],[5],[7]	0.75	[3],[5],[7]	0.10	[3],[5],[7]	0.81	[3],[5],[7]	5.13	[2],[4],[6]	2.18	[3],[5],[7]	$ 2.23
Dividends per share of common stock	0.4750		0.4625		0.4625		0.4625		0.4625		0.4400		0.4400		0.44		1.8625		1.7825
High	58.96		58.95		57.24		58.86		54.68		49.90		44.60		42.09		58.96		54.68
Low	$ 53.10		$ 51.28		$ 49.60		$ 49.62		$ 43.55		$ 41.08		$ 39.24		$ 32.50		$ 49.60		$ 32.50

[1] Net sales are attributed to countries based on the location of the seller.

[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

[3] 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

[4] Includes the operating earnings of the North American Consumer Packaging business for the full year. Also includes the following pre-tax charges (gains): 2017In millions Q1 Q2 Q3 Q4North American Consumer Packaging transaction costs $— $— $— $17Non-operating pension expense — — — 45Total $— $— $— $62

[5] Includes the operating earnings of the North American Consumer Packaging business for the full year and a pre-tax charge of $8 million for a legal settlement associated with the xpedx business.

[6] Includes the following tax expenses (benefits): 2017 In millions Q1 Q2 Q3 Q4 International legal entity restructuring $15 $— $19 $— Income tax refund claims — (85) — (28) Cash pension contribution — 38 — — International Tax Law Change — — — 9 Tax benefit of Tax Cuts and Jobs Act — — — (1,222) Tax impact of other special items (8) (137) (8) (41) Total $7 $(184) $11 $(1,282)

[7] Includes the following tax expenses (benefits): 2016In millions Q1 Q2 Q3 Q4Cash pension contribution $— $23 $— $—U.S. Federal audit (14) — — —Brazil goodwill (57) — — —International legal entity restructuring — (6) — —Luxembourg tax rate change — — — 31Tax impact of other special items (3) (10) (24) (14)Total $(74) $7 $(24) $17