Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]

In accordance with the provisions of ASC 820, the following tables provide the valuation hierarchy classification of assets and liabilities that are carried at fair value and measured on a recurring basis in our Consolidated Balance Sheet as of December 31, 2020 and 2019:

	December 31, 2020
(dollars in millions)	Total		Level 1		Level 2		Level 3
Recurring fair value measurements:
Marketable securities held in trusts	$	881	$	773	$	108	$	—
Derivative assets	241		—		241		—
Derivative liabilities	(98)		—		(98)		—

	December 31, 2019
(dollars in millions)	Total		Level 1		Level 2		Level 3
Recurring fair value measurements:
Available-for-sale securities	$	53	$	53	$	—	$	—
Derivative assets	46		—		46		—
Derivative liabilities	(282)		—		(282)		—

Fair Value, by Balance Sheet Grouping [Table Text Block]

The following table provides carrying amounts and fair values of financial instruments that are not carried at fair value in our Consolidated Balance Sheet at December 31:

	2020				2019
(dollars in millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Customer financing notes receivable	$	271	$	264	$	220	$	220
Short-term borrowings	(247)		(247)		(2,293)		(2,293)
Long-term debt (excluding finance leases)	(31,512)		(38,615)		(40,883)		(45,887)
Long-term liabilities	(27)		(25)		(334)		(320)

The following table provides the valuation hierarchy classification of assets and liabilities that are not carried at fair value in our Consolidated Balance Sheet as of December 31, 2020 and 2019:

	December 31, 2020
(dollars in millions)	Total		Level 1		Level 2		Level 3
Customer financing notes receivable	$	264	$	—	$	264	$	—
Short-term borrowings	(247)		—		(160)		(87)
Long-term debt (excluding finance leases)	(38,615)		—		(38,540)		(75)
Long-term liabilities	(25)		—		(25)		—

	December 31, 2019
(dollars in millions)	Total		Level 1		Level 2		Level 3
Customer financing notes receivable	$	220	$	—	$	220	$	—
Short-term borrowings	(2,293)		—		—		(2,293)
Long-term debt (excluding finance leases)	(45,887)		—		(45,802)		(85)
Long-term liabilities	(320)		—		(320)		—