Investments of Insurance Subsidiaries (Tables)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments

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

	2017
	Amortized Cost		Unrealized Amounts				Fair Value
			Gains		Losses
States and municipalities 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

	2016
	Amortized Cost		Unrealized Amounts					Fair Value
			Gains		Losses
States and municipalities debt securities	$	345	$	9	$	(1	)	$	353
Money market funds and other		29		3		—			32
	$	374	$	12	$	(1	)		385
Amounts classified as current assets									(49	)
Investment carrying value								$	336

Schedule of Maturities of Investments

Scheduled maturities of investments in debt securities at December 31, 2017 were as follows (dollars in millions):

	Amortized Cost		Fair Value
Due in one year or less	$	31	$	31
Due after one year through five years		84		86
Due after five years through ten years		187		194
Due after ten years		59		60
	$	361	$	371