United states securities and exchange commission

1. Debt securities with maturities of less than one year at the time of acquisition.

2. U.S. Treasury obligations, U.S. agency obligations, agency mortgage-backed securities and other municipalities' obligations.

3. Cost includes fair value adjustments of $511 million at December 31, 2017 and $18 million at December 31, 2016.

4. Presented net of cash collateral.

Cost approximates fair value for all other financial instruments.

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Table of Contents


Investments

The following table provides the investing results from available-for-sale securities for the years ended December 31, 2017 , 2016 and 2015 .

Investing Results
In millions	2017			2016			2015
Proceeds from sales of available-for-sale securities	$	1,078		$	535		$	565
Gross realized gains	$	120		$	58		$	96
Gross realized losses	$	(10	)	$	(2	)	$	(14	)

The following table summarizes the contractual maturities of the Company’s investments in debt securities:

Contractual Maturities of Debt Securities at Dec 31, 2017	Amortized Cost			Fair Value
In millions
Within one year	$	7		$	7
One to five years	370			378
Six to ten years	680			682
After ten years	284			305
Total	$	1,341		$	1,372

At December 31, 2017 , the Company had $6,418 million ( $3,934 million at December 31, 2016 ) of held-to-maturity securities (primarily treasury bills and time deposits) classified as cash equivalents, as these securities had maturities of three months or less at the time of purchase. The Company’s investments in held-to-maturity securities are held at amortized cost, which approximates fair value. At December 31, 2017 , the Company had investments in money market funds of $509 million classified as cash equivalents ( $239 million at December 31, 2016 ) and $558 million classified as "Other current assets" in the consolidated balance sheets ( zero at December 31, 2016 ) due to the restricted nature of its use. See Note 19 for additional information.

At December 31, 2017, the Company had $952 million of held-to-maturity securities (primarily time deposits) classified as "Marketable securities" in the consolidated balance sheets as these securities had maturities of more than three months to less than one year at the time of purchase ( zero at December 31, 2016 ). In 2017, $2,938 million of these marketable securities matured.
The following tables provide the fair value and gross unrealized losses of the Company’s investments that were deemed to be temporarily impaired at December 31, 2017 and 2016 , aggregated by investment category:

Temporarily Impaired Securities at Dec 31, 2017	Less than 12 months						12 months or more						Total
	Fair Value			Unrealized losses			Fair Value			Unrealized losses			Fair Value			Unrealized losses
In millions
Government debt 1	$	295		$	(4	)	$	151		$	(7	)	$	446		$	(11	)
Corporate bonds	163			(2		)	19			(1		)	182			(3		)
Equity securities	7			(2		)	63			(24		)	70			(26		)
Total temporarily impaired securities	$	465		$	(8	)	$	233		$	(32	)	$	698		$	(40	)

1. U.S. Treasury obligations, U.S. agency obligations, agency mortgage-backed securities and other municipalities' obligations.

Temporarily Impaired Securities at Dec 31, 2016	Less than 12 months						12 months or more						Total
	Fair Value			Unrealized losses			Fair Value			Unrealized losses			Fair Value			Unrealized losses
In millions
Government debt 1	$	351		$	(12	)	$	—		$	—		$	351		$	(12	)
Corporate bonds	193			(4		)	16			(1		)	209			(5		)
Equity securities	48			(6		)	163			(44		)	211			(50		)
Total temporarily impaired securities	$	592		$	(22	)	$	179		$	(45	)	$	771		$	(67	)