Pension and Other Postretirement Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 CAD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 CAD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CAD ($)
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Expense for the defined contribution plans, total	$ 18		$ 17		$ 18
Decrease in pension benefit obligation for sales			98
Total benefit obligations for pension plans with benefit obligations in excess of plan assets	4,612		5,067
Total fair value of plan assets for pension plans with benefit obligations in excess of plan assets	3,570		3,627
Total accumulated benefit obligations for pension plans with accumulated benefit obligations in excess of plan assets	4,588		5,034
Total fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets	3,570		3,627
Total accumulated benefit obligations for all pension plans	4,873		5,212
Estimated pension contributions in the next fiscal year	$ 77
Additional contribution per metric ton of capacity reduced due to downtime required under the Canadian pension funding relief regulations		$ 75
Additional contribution per metric ton of capacity reduced due to downtime required under the Canadian pension funding relief regulations, payment period	4 years	4 years
Additional contribution per metric ton of capacity reduced due to downtime required under the Canadian pension funding relief regulations, period covering cumulative period of downtime threshold	18 months	18 months
Annual additional contribution related to downtime under the Canadian pension funding relief regulations				$ 2,000,000		$ 4,000,000
Sales of Level 3 plan assets			98
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Paper mill at Thorold (Ontario)
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Curtailments, settlements and other (gains) losses			$ 28
Equity Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	45.00%
Real Assets
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	10.00%
Debt Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	45.00%
Minimum | Equity Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	25.00%
Minimum | Real Assets
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	0.00%
Minimum | Debt Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	35.00%
Maximum | Equity Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	55.00%
Maximum | Real Assets
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	15.00%
Maximum | Debt Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	65.00%
Near-Term Liquidity | Maximum
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	5.00%
Ontario
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Solvency funded status below which funding on solvency basis required	85.00%	85.00%
United States and Canada | Equity Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Targeted asset allocation of plan assets (as a percent)	60.00%