Available-for-sale securities (Tables)

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Schedule of available-for-sale securities

	December 31, 2014						December 31, 2013							December 31, 2012
(Millions of dollars)	Cost Basis		Unrealized Pretax Net Gains (Losses)		Fair Value		Cost Basis		Unrealized Pretax Net Gains (Losses)			Fair Value		Cost Basis		Unrealized Pretax Net Gains (Losses)			Fair Value
Government debt
U.S. treasury bonds	$	10	$	—	$	10	$	10	$	—		$	10	$	10	$	—		$	10
Other U.S. and non-U.S. government bonds	94		—		94		119		1			120		144		2			146
Corporate bonds
Corporate bonds	677		16		693		612		21			633		626		38			664
Asset-backed securities	103		2		105		72		—			72		96		—			96
Mortgage-backed debt securities
U.S. governmental agency	292		2		294		322		(1		)	321		291		8			299
Residential	15		—		15		18		—			18		26		(1		)	25
Commercial	63		4		67		87		6			93		117		10			127
Equity securities
Large capitalization value	150		83		233		173		81			254		147		38			185
Smaller company growth	17		26		43		25		24			49		22		12			34
Total	$	1,421	$	133	$	1,554	$	1,438	$	132		$	1,570	$	1,479	$	107		$	1,586

Investments in an unrealized loss position that are not other-than-temporarily impaired

Investments in an unrealized loss position that are not other-than-temporarily impaired:
	December 31, 2014
	Less than 12 months 1				12 months or more 1				Total
(Millions of dollars)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate bonds
Corporate bonds	$	195	$	1	$	32	$	—	$	227	$	1
Mortgage-backed debt securities
U.S. governmental agency	34		—		140		3		174		3
Equity securities
Large capitalization value	15		2		1		—		16		2
Total	$	244	$	3	$	173	$	3	$	417	$	6

¹  Indicates length of time that individual securities have been in a continuous unrealized loss position.

Investments in an unrealized loss position that are not other-than-temporarily impaired:
	December 31, 2013
(Millions of dollars)	Less than 12 months 1				12 months or more 1				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate bonds
Corporate bonds	$	159	$	2	$	1	$	—	$	160	$	2
Asset-backed securities	6		—		20		1		26		1
Mortgage-backed debt securities
U.S. governmental agency	140		4		65		2		205		6
Total	$	305	$	6	$	86	$	3	$	391	$	9

¹  Indicates length of time that individual securities have been in a continuous unrealized loss position.

Investments in an unrealized loss position that are not other-than-temporarily impaired:
	December 31, 2012
(Millions of dollars)	Less than 12 months 1				12 months or more 1				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate bonds
Asset-backed securities	$	—	$	—	$	20	$	3	$	20	$	3
Mortgage-backed debt securities
U.S. governmental agency	84		1		15		—		99		1
Residential	—		—		14		1		14		1
Equity securities
Large capitalization value	25		2		10		1		35		3
Total	$	109	$	3	$	59	$	5	$	168	$	8

¹  Indicates length of time that individual securities have been in a continuous unrealized loss position.

Cost basis and fair value of the available-for-sale debt securities by contractual maturity

	December 31, 2014
(Millions of dollars)	Cost Basis		Fair Value
Due in one year or less	$	72	$	73
Due after one year through five years	744		760
Due after five years through ten years	41		42
Due after ten years	27		27
U.S. governmental agency mortgage-backed securities	292		294
Residential mortgage-backed securities	15		15
Commercial mortgage-backed securities	63		67
Total debt securities – available-for-sale	$	1,254	$	1,278

Schedule of proceeds and gross gain and losses from the sale of available-for-sale securities

Sales of Securities:
	Years Ended December 31,
(Millions of dollars)	2014		2013		2012
Proceeds from the sale of available-for-sale securities	$	434	$	449	$	306
Gross gains from the sale of available-for-sale securities	$	38	$	22	$	6
Gross losses from the sale of available-for-sale securities	$	2	$	2	$	—