XML 58 R47.htm IDEA: XBRL DOCUMENT v3.10.0.1
PARTNERS' EQUITY - Class B Units (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2018
Mar. 31, 2018
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
PARTNERS' EQUITY          
Amount of Class B distribution     $ 197    
Class B Units          
PARTNERS' EQUITY          
Limited Partners, Distributions paid     15 $ 22  
Distributions | Class B Units          
PARTNERS' EQUITY          
Amount of Class B distribution     $ 11    
Limited Partners, Distributions paid   $ 15      
TransCanada | Distributions | Class B Units          
PARTNERS' EQUITY          
Percentage of reduction in distributions payable     35.00%    
TransCanada | Distributions | Common Units          
PARTNERS' EQUITY          
Percentage of reduction in distributions payable     35.00%    
Minimum distribution payable per common unit     $ 3.94    
GTN | TransCanada | Distributions | Class B Units          
PARTNERS' EQUITY          
Portion of GTN's annual distributions to which the Class B units are entitled to receive a percentage share of the distributions above threshold (as a percent)     30.00%    
Percentage applied to 30 percent of GTN's distributions above threshold through March 31, 2020     100.00%    
Threshold of GTN's total distributable cash flows for payment to Class B units     $ 20    
Percentage applied to 30 percent of GTN's distributions above threshold after March 31, 2020     25.00%    
Percentage applied to GTN's distributable cash flow     30.00% 30.00%  
30% of GTN's distributable cash flow     $ 31 $ 28  
Threshold of GTN's distributions for payment to Class B units $ 20   20   $ 20
Increase in equity account     $ 4