Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating Activities
Net income	$ 103	$ 102
Loss from discontinued operations, net of tax	0	(1)
Income from continuing operations	103	103
Adjustments to reconcile net income to net cash:
Depreciation, depletion and amortization	72	77
Loss on extinguishment of debt	19	0
Share-based compensation expense	6	10
Deferred income taxes	1	4
Gain on asset dispositions	7	12
Income from equity method investments	(22)	(8)
Dividends received from equity method investments	18	0
Gain on deconsolidation of subsidiaries and consolidated joint ventures	0	(27)
(Increase) decrease in working capital, net of deconsolidation of subsidiaries and consolidated joint ventures:
IncreaseDecreaseInReceivables	66	54
Income taxes receivable	(1)	(1)
Inventories	6	(17)
Other current assets	1	(1)
Payables	(33)	(18)
Accrued expenses	(25)	(22)
Decrease in other assets	1	0
Decrease in pension and other postretirement benefits	(40)	0
Decrease in other liabilities	(4)	(7)
Other, net	5	(7)
Net cash provided by operating activities	34	20
Investing Activities
Purchases of marketable securities	(32)	(97)
Sales or maturities of marketable securities	103	99
Capital expenditures	(48)	(58)
Net proceeds from asset dispositions	42	14
Investment in joint ventures, including $23 of cash of contributed subsidiaries in 2014	0	(557)
Insurance proceeds	2	2
Return (deposit) of restricted cash	(49)	4
Net cash provided by (used for) investing activities	18	(593)
Financing Activities
Issuance of debt	350	3
Repayment of debt	(386)	(2)
Payment of debt issuance fees	(6)	0
Issuance of common stock	4	3
Repurchases of common stock to satisfy employee tax withholding obligations	(8)	(5)
Net cash used for financing activities	(46)	(1)
Effect of exchange rate changes on cash	(3)	0
Net cash used for operating activities - discontinued operations	0	(1)
Net increase (decrease) in cash and cash equivalents	3	(575)
Cash and cash equivalents at beginning of period	228	810
Cash and cash equivalents at end of period	231	235
Supplemental Cash Flow Disclosures:
Interest paid, net of capitalized interest	80	86
Income taxes paid, net	1	8
Noncash Investing and Financing Activities:
Amount in accounts payable for capital expenditures	6	6
Contribution of wholly-owned subsidiaries and joint venture investments as consideration for investment in USG Boral Building Products	0	121
Conversion of $75 million of 10% convertible senior notes due 2018, net of discount	0	(73)
Issuance of common stock upon conversion of debt	0	75
Accrued interest on debt conversion	$ 0	$ (2)