Income Taxes - Schedule of Amount and Expiration Dates of Operating Loss and Tax Credit Carry-forwards (Details) $ in Millions	Dec. 31, 2021 USD ($)
Operating Loss And Tax Credit Carryforwards [Line Items]
Total	$ 2,719
Canadian net operating loss carryforwards
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	728
Canadian capital loss carryforwards
Operating Loss And Tax Credit Carryforwards [Line Items]
Capital loss carryforwards	866
Canadian tax credits
Operating Loss And Tax Credit Carryforwards [Line Items]
U.S. foreign tax credits	3
U.S. state net operating loss carryforwards
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	680
U.S. capital loss carryforwards
Operating Loss And Tax Credit Carryforwards [Line Items]
Capital loss carryforwards	16
U.S. foreign tax credits
Operating Loss And Tax Credit Carryforwards [Line Items]
U.S. foreign tax credits	112
Foreign tax
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	207
Capital loss carryforwards	30
Other foreign net operating loss carryforwards
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	$ 77