Accrued expenses and other long-term liabilities consisted of the following (in millions):



	Accrued Expenses				Other Long- Term Liabilities
	December 31,
	2015		2014		2015		2014
Defined benefit plan liabilities (see Note 13)	$	40	$	48	$	719	$	792
Wage and other employee-related liabilities	292		294		100		104
Uncertain income tax position liabilities (see Note 15) ^(a)	—		—		148		316
Environmental liabilities	27		26		231		269
Accrued interest expense	96		88		—		—
Asset retirement obligations	19		20		64		71
Other accrued liabilities	80		120		349		387
Accrued expenses and other long-term liabilities	$	554	$	596	$	1,611	$	1,939

^{___________________________}

^(a)As of December 31, 2015, our net liability for uncertain tax positions, including related penalties and interest, was $391 million. Of this amount, $438 million was classified as a current liability and reflected in income taxes payable, and $148 million was classified as a long-term liability and reflected in other long-term liabilities as detailed in this table. These liabilities were reduced by a $195 million receivable classified as a long-term asset and reflected in “deferred charges and other assets, net.” As of December 31, 2014, our total liability for uncertain tax positions, including related penalties and interest, was $484 million, with $168 million classified as a current liability and reflected in income taxes payable and the remaining $316 million classified as a long-term liability and reflected in other long-term liabilities as detailed in this table.