Debt and Credit Facilities (Tables)

9 Months Ended

Sep. 30, 2018

Long-term Debt, Unclassified [Abstract]

Schedule of Long-term Debt Instruments

Summary of Total Debt			September 2018		December 2017
Senior unsecured notes:
	Rate	Due
	1.300%	April 1, 2018	$	—	$	600
	1.800%	January 15, 2019	500		499
	2.000%	March 8, 2019	749		748
	4.375%	January 15, 2020	499		498
	2.625%	March 15, 2021	747		746
	3.375%	May 15, 2024	584		598
	3.375%	November 1, 2025	746		745
	3.500%	March 15, 2026	989		988
	3.650%	March 7, 2028	595		—
	4.100%	April 1, 2043	391		391
	4.375%	May 15, 2044	395		394
	4.625%	March 15, 2046	980		980
Other			28		35
Total debt			$	7,203	$	7,222
Less current maturities of debt			1,275		632
Total long-term debt			$	5,928	$	6,590
Unamortized debt issuance costs			$	39	$	39
Available borrowing capacity			$	1,553	$	1,547
Fair value of senior unsecured notes			$	7,118	$	7,521