Accumulated Other Comprehensive Income (Loss) (Tables)

3 Months Ended

Mar. 31, 2021

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Summary of Changes in Accumulated Other Comprehensive Income (Loss)

Changes in Accumulated Other Comprehensive Income (Loss) by Component

	Foreign Exchange Translation Adjustment		Changes in Fair Value of Effective Cash Flow Hedges		Pension Adjustments			Total Accumulated Other Comprehensive Income (Loss)
	(Dollars in millions)
Balance at December 31, 2019	$	153	$	4	$	(27	)	$	130
Other comprehensive income (loss) before    reclassifications		39		—		—			39
Amounts reclassified from accumulated other    comprehensive income (loss)		—		—		—			—
Net current period other comprehensive income (loss)		39							39
Balance at March 31, 2020	$	192	$	4	$	(27	)	$	169

	Foreign Exchange Translation Adjustment			Changes in Fair Value of Effective Cash Flow Hedges			Pension Adjustments			Total Accumulated Other Comprehensive Income (Loss)
	(Dollars in millions)
Balance at December 31, 2020	$	(81	)	$	(3	)	$	(45	)	$	(129	)
Other comprehensive (loss) before    reclassifications		110			—			—			110
Amounts reclassified from accumulated other    comprehensive income (loss)		—			1			—			1
Net current period other comprehensive (loss)		110			1						111
Balance at March 31, 2021	$	29		$	(2	)	$	(45	)	$	(18	)