Debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Total Debt

Our total debt, including short-term and long-term debt, consisted of the following as of December 31, 2017 and 2016 (in millions):

	As of December 31,
	2017		2016
Debt:
Short-term debt:
Commercial Paper	$	1,233	$	1,642
2018 Senior Notes (2.50% senior unsecured notes due October 15, 2018)	600		—
NYSE Notes (2.00% senior unsecured notes due October 5, 2017)	—		851
Total short-term debt	1,833		2,493
Long-term debt:
2018 Senior Notes (2.50% senior unsecured notes due October 15, 2018)	—		598
2020 Senior Notes (2.75% senior unsecured notes due December 1, 2020)	1,244		1,242
2022 Senior Notes (2.35% senior unsecured notes due September 15, 2022)	495		—
2023 Senior Notes (4.00% senior unsecured notes due October 15, 2023)	791		790
2025 Senior Notes (3.75% senior unsecured notes due December 1, 2025)	1,242		1,241
2027 Senior Notes (3.10% senior unsecured notes due September 15, 2027)	495		—
Total long-term debt	4,267		3,871
Total debt	$	6,100	$	6,364

Debt Repayment Schedule

As of December 31, 2017, the outstanding debt repayment schedule is as follows (in millions):

2018	$	1,835
2019	—
2020	1,250
2021	—
2022	500
Thereafter	2,550
Principal amounts repayable	6,135
Debt issuance costs	(27		)
Unamortized balance of fair value adjustments and discounts on bonds, net	(8		)
Total debt outstanding	$	6,100