Credit Facilities (Tables)

12 Months Ended

Dec. 31, 2020

Line of Credit Facility [Abstract]

Schedule of Short-term Debt [Table Text Block]

Short-term borrowings under these credit facilities, and related interest rates, are reflected in the following table (dollars in millions).

	Year Ended December 31,
	2020			2019
Average daily amount of short-term debt outstanding	$	131		$	7
Weighted daily average interest rate *	1.5		%	2.6		%
Maximum amount outstanding during the year	$	225		$	46

*    Excludes the effect of commitment fees, facility fees and other financing fees.