The carrying value of debt outstanding, net of unamortized debt issuance costs, was as follows at September 30, 2017 and December 31, 2016:



	September 30, 2017		December 31, 2016
	(in millions)
Short-term:
Commercial paper	$	150	$	300
$500 million, 7.20% Senior notes due June 15, 2018	501		—
$300 million, 6.30% Senior notes due August 1, 2018	302		—
Total short-term debt	953		300

Long-term:
Senior notes:
$500 million, 7.20% due June 15, 2018	—		501
$300 million, 6.30% due August 1, 2018	—		304
$400 million, 2.625% due October 1, 2019	399		398
$600 million, 3.15% due December 1, 2022	596		595
$600 million, 3.85% due October 1, 2024	595		595
$600 million, 3.95% due March 15, 2027	594		—
$250 million, 8.15% due June 15, 2038	263		264
$400 million, 4.625% due December 1, 2042	396		396
$750 million, 4.95% due October 1, 2044	739		739
$400 million, 4.80% due March 15, 2047	395		—
Total long-term debt	3,977		3,792

Total debt	$	4,930	$	4,092