Leases (Direct Finance and Sales-type Leases) (Details) - CAD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Net investment in direct finance and sales-type leases
Total minimum lease payments to be received	$ 1,018	$ 1,066
Less: amounts representing estimated executory costs	(179)	(189)
Minimum lease payments receivable	839	877
Estimated residual value of leased property (unguaranteed)	183	183
Less: unearned finance lease income	(487)	(532)
Net investment in direct finance and sales-type leases	535	528
Principal due within one year (included in "Receivables and other current assets")	18	17
Net investment in sales-type leases - long-term (included in "Other long-term assets")	42	38
Net Investment in direct finance leases - long-term	475	473
Future minimum lease payments to be received for each of the next five years and in aggregate thereafter
2021	78
2022	77
2023	76
2024	77
2025	79
Thereafter	631
Total minimum lease payments to be received	1,018	1,066
Less: executory costs	(179)	(189)
Minimum lease payments receivable	$ 839	$ 877

Amount of net investment in sales-type lease, classified as noncurrent.

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- Definition

Amount of deferred selling profit from direct financing lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919379-209981

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Amount of net investment in sales-type and direct financing lease.

+ References

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Amount of net investment in sales-type and direct financing lease, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121561866&loc=SL77919306-209978

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-Publisher FASB
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-Topic 842
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-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121561866&loc=SL77919308-209978

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Amount of net investment in sales-type and direct financing lease, classified as noncurrent.

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- Definition

Amount of residual asset covered by residual value guarantee. Excludes guarantee considered to be lease payments for lessor.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 7
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919381-209981

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- Definition

Present value of lease payments not yet received by lessor and amount expected to be derived from underlying asset, following end of lease term guaranteed by lessee or other third party unrelated to lessor, from sales-type and direct financing leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919391-209981

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-Publisher FASB
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-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121576215&loc=SL77919379-209981

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases.

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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- Definition

Amount of undiscounted lease receivable in excess of discounted receivable for sales-type and direct financing leases.

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