Investments (Tables)

12 Months Ended

Dec. 31, 2015

Investments

Summary of the amortized cost and estimated fair value of short-term investments for both available-for-sale and trading securities

	December 31, 2015				December 31, 2014
	Amortized		Fair		Amortized		Fair
(Millions of dollars)	Cost		Value		Cost		Value
Money market funds	$	81	$	81	$	142	$	142
Corporate bonds		—		—		11		11
U.S. Government agency securities		—		—		10		10
Other available-for-sale securities		—		—		4		4
Total available-for-sale short-term investments		81		81		167		167
Domestic equity securities		475		466		115		115
Domestic debt securities		452		450		5		5
Foreign equity securities		120		120		—		—
High yield debt securities		108		104		188		182
Money market funds held in trading accounts		22		22		21		21
Collateralized loan obligation		10		10		—		—
Other trading securities		1		1		1		1
Total trading short-term investments		1,188		1,173		330		324
Total short-term investments	$	1,269	$	1,254	$	497	$	491