Investments of Insurance Subsidiaries (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments

A summary of the insurance subsidiaries’ investments at December 31 follows (dollars in millions):

	2018
	Amortized Cost		Unrealized Amounts					Fair Value
			Gains		Losses
Debt securities	$	338	$	5	$	(2	)	$	341
Money market funds and other		68		—		—			68
	$	406	$	5	$	(2	)		409
Amounts classified as current assets									(47	)
Investment carrying value								$	362

	2017
	Amortized Cost		Unrealized Amounts				Fair Value
			Gains		Losses
Debt securities	$	361	$	10	$	—	$	371
Money market funds and other		101		—		—		101
	$	462	$	10	$	—		472
Amounts classified as current assets								(54	)
Investment carrying value							$	418

Schedule of Maturities of Investments

Scheduled maturities of investments in debt securities at December 31, 2018 were as follows (dollars in millions):

	Amortized Cost		Fair Value
Due in one year or less	$	3	$	3
Due after one year through five years		64		65
Due after five years through ten years		201		203
Due after ten years		70		70
	$	338	$	341