Marketable Securities and Restricted Funds (Tables)

9 Months Ended

Sep. 30, 2016

Investments, Debt and Equity Securities [Abstract]

Restricted and Nonrestricted AFS Securities by Balance Sheet Classification

AFS Securities. AFS Securities are as follows:

	Estimated Fair Value
	September 30, 2016		December 31, 2015
	(in millions)
Corporate debt securities (a)	$	20	$	31
Canadian equity securities (b)	17		—
Total available-for-sale securities	$	37	$	31

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(a) Amounts related to certain construction projects.

(b) Amounts related to restricted funds held and collected from customers of Western Canada Transmission & Processing and Express-Platte for Canadian pipeline abandonment in accordance with the NEB’s regulatory requirements.

Our AFS securities are classified on the Condensed Consolidated Balance Sheets as follows:

	Estimated Fair Value
	September 30, 2016		December 31, 2015
	(in millions)
Restricted funds
Investments and other assets—other	$	31	$	11
Non-restricted funds
Current assets—other	6		20
Total available-for-sale securities	$	37	$	31

Estimated Fair Values of Held to Maturity Marketable Securities

HTM Securities. HTM securities are as follows:

		Estimated Fair Value
Description	Condensed Consolidated Balance Sheets Caption	September 30, 2016		December 31, 2015
		(in millions)
Bankers acceptances	Current assets—other	$	44	$	30
Canadian government securities	Current assets—other	25		24
Money market securities	Current assets—other	8		3
Canadian government securities	Investments and other assets—other	52		50
Bankers acceptances	Investments and other assets—other	—		12
Total held-to-maturity securities		$	129	$	119