Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 1,973	$ 1,518
Funds deposited by counterparties	2	106
Restricted cash	446	414
Accounts receivable — trade	1,166	1,157
Inventory	1,111	1,252
Derivative instruments	1,062	1,915
Cash collateral posted in support of energy risk management activities	203	568
Current assets held-for-sale	9	6
Prepayments and other current assets	423	455
Total current assets	6,395	7,391
Property, plant and equipment, net	17,912	18,732
Other Assets
Equity investments in affiliates	1,120	1,045
Notes receivable, less current portion	17	53
Goodwill	662	999
Intangible assets, net	2,036	2,310
Nuclear decommissioning trust fund	610	561
Derivative instruments	189	305
Deferred income taxes	225	167
Non-current assets held-for-sale	10	105
Other non-current assets	1,179	1,214
Total other assets	6,048	6,759
Total Assets	30,355	32,882
Current Liabilities
Current portion of long-term debt and capital leases	1,220	481
Accounts payable	895	869
Derivative instruments	1,084	1,721
Cash collateral received in support of energy risk management activities	2	106
Accrued interest expense	220	242
Other accrued expenses	543	568
Current liabilities held-for-sale	0	2
Other current liabilities	418	386
Total current liabilities	4,382	4,375
Other Liabilities
Long-term debt and capital leases	18,006	18,983
Nuclear decommissioning reserve	287	326
Nuclear decommissioning trust liability	339	283
Postretirement and other benefit obligations	553	588
Deferred income taxes	20	19
Derivative instruments	294	493
Non-current liabilities held-for-sale	12	4
Off-market Lease, Unfavorable	1,040	1,146
Other non-current liabilities	930	900
Total non-current liabilities	21,481	22,742
Total Liabilities	25,863	27,117
2.822% convertible perpetual preferred stock; $0.01 par value; 250,000 shares issued and outstanding at December 31, 2015	0	302
Redeemable noncontrolling interest in subsidiaries	46	29
Stockholders' Equity
Common stock; $0.01 par value; 500,000,000 shares authorized; 417,583,825 and 416,939,950 shares issued; and 315,443,011 and 314,190,042 shares outstanding at December 31, 2016 and 2015	4	4
Additional paid-in capital	8,358	8,296
Accumulated deficit	(3,787)	(3,007)
Treasury stock, at cost; 102,140,814 and 102,749,908 shares at December 31, 2016 and 2015	(2,399)	(2,413)
Accumulated other comprehensive loss	(135)	(173)
Noncontrolling interest	2,405	2,727
Total Stockholders' Equity	4,446	5,434
Total Liabilities and Stockholders' Equity	$ 30,355	$ 32,882