Financial Instruments (Narrative) (Details) $ in Millions, $ in Billions |
1 Months Ended | 3 Months Ended | 12 Months Ended | |||||
---|---|---|---|---|---|---|---|---|
Mar. 31, 2019
USD ($)
|
Mar. 31, 2019
CAD ($)
|
Mar. 31, 2019
CAD ($)
|
Mar. 31, 2019
USD ($)
|
Dec. 31, 2020
USD ($)
|
Dec. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
Mar. 31, 2019
CAD ($)
|
|
Derivative [Line Items] | ||||||||
Loss on Cronos-related financial instruments | $ 140 | $ 1,442 | $ 0 | |||||
Cronos [Member] | ||||||||
Derivative [Line Items] | ||||||||
Payments to acquire equity method investments and derivative instruments, investing | $ 1,800 | $ 2.4 | $ 2.4 | |||||
Not Designated as Hedging Instrument [Member] | Forward Contracts [Member] | ||||||||
Derivative [Line Items] | ||||||||
Derivative asset, notional amount | $ 1,800 | $ 1,800 | $ 2.4 | |||||
Loss on Cronos-related financial instruments | $ 31 |