Debt (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Components of Notes Payable

	September 30, 2017				December 31, 2016
(millions)	Principal amount		Effective interest rate (a)		Principal amount		Effective interest rate (a)
U.S. commercial paper	$	285	1.29	%	$	80	0.61	%
Europe commercial paper	201		(0.26	)%	306		(0.18	)%
Bank borrowings	86				52
Total	$	572			$	438

(a) Negative effective interest rates on certain borrowings in Europe are the result of efforts by the European Central Bank to stimulate the economy in the eurozone.