Share-Based Payments - Total Shareholder Return Units Narrative (Details) - Total Shareholder Return Units (TSRUs) [Member] |
12 Months Ended | |
|---|---|---|
|
Oct. 26, 2016
USD ($)
Employee
trading_day
|
Dec. 31, 2018
Employee
trading_day
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Trading day average used to calculate the conversion | trading_day | 20 | 20 |
| Age of eligible unit holder which can elect to exercise and convert TSRUs when vested into PTUs | 55 years | |
| Award requisite service period | 10 years | |
| Number of employees affected by plan modification | Employee | 2,900 | 260 |
| Incremental compensation cost resulting from plan modification | $ | $ 0 | |
| Minimum [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Contractual term (years) | 5 years | |
| Maximum [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Contractual term (years) | 7 years |