Property sale	12 Months Ended
Dec. 31, 2022
Discontinued Operations and Disposal Groups [Abstract]
Property sale	Property saleDuring the first quarter of 2021, the Company exchanged property and property easements in Chicago with a government agency for proceeds of $103 million including cash of $61 million and property and permanent easement assets at a fair value of $33 million and $9 million, respectively. Fair value was determined based on comparable market transactions. The Company recorded a gain within "Purchased services and other" of $50 million ($38 million after tax) from the transaction, and a deferred gain of $53 million, which is being recognized in income over the period of use of certain easements. The Company recognized $14 million of the deferred gain into income in 2022 (2021 – $13 million).

The entire disclosure related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-URI https://asc.fasb.org/topic&trid=2155823

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-URI https://asc.fasb.org/subtopic&trid=2122178

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