Short-Term Debt (Tables)
 12 Months Ended
Dec. 31, 2019
Short-term Debt [Abstract]  
Schedule of Company's Aggregate Credit Facility Commitments, Letter of Credit Sub-Limit Under Revolving Credit Facility and Commercial Paper Limit and Available Capacity
Presented in the table below are the aggregate credit facility commitments, letter of credit sublimit under the revolving credit facility and the commercial paper limit, as well as the available capacity for each, as of December 31, 2019 and 2018:

Credit Facility Commitment
 
Available Credit Facility Capacity
 
Letter of Credit Sublimit
 
Available Letter of Credit Capacity
 
Commercial Paper Limit
 
Available Commercial Paper Capacity
December 31, 2019
$
2,250

 
$
2,174

 
$
150

 
$
74

 
$
2,100

 
$
1,314

December 31, 2018
2,262

 
2,177

 
150

 
69

 
2,100

 
1,146
Schedule Of Short-Term Borrowings Activity
Presented in the table below is the short-term borrowing activity for AWCC for the years ended December 31:
  
2019
 
2018
Average borrowings
$
726

 
$
1,029

Maximum borrowings outstanding
1,271

 
1,905

Weighted average interest rates, computed on daily basis
2.54
%
 
2.28
%
Weighted average interest rates, as of December 31
1.86
%
 
2.84
%