Please calculate the free cash flow for 2012 and explain the meaning of this ratio

Cash flow from operating activities	In millions	In millions
	For the year ended 2012	For the year ended 2011
Net (loss) earnings	$(12,650)	$7,074
Depreciation and amortization	5,095	4,984
Impairment of goodwill and purchased intangible assets	18,035	885
Stock-based compensation expense	635	685
Provision for doubtful accounts	142	81
Provision for inventory	277	217
Restructuring charges	2,266	645
Deferred taxes on earnings	(711)	166
Excess tax benefit from stock-based competition	(12)	(163)
Other, net	265	(46)
Accounts and financing receivables	1,269	(227)
Inventory	890	(1,252)
Accounts payable	(1,414)	275
Taxes on earnings	(320)	610
Restructuring	(840)	(1,002)
Other assets and liabilities	(2,356)	(293)
Net cash provided by operating activities	10,571	12,639
Cash flows from investing activities:
Investment in property, plant, and equipment	(3,706)	(4,539)
Proceeds from sale of property, plant, and equipment	617	999
Purchases of available-for-sale securities and other investments	(972)	(96)
Maturities and sales of available-for-sale securities and other investment	662	68
Payments in connection with business acquisitions, net of cash acquired	(141)	(10,480)
Proceeds from business divestiture, net	87	89
Net cash used in investing activities	(3,453)	(13,959)
Cash flow from financing activities:
(Payments) issuance of commercial paper and notes payable, net	(2,775)	(1,270)
Issuance of debt	5,154	11,942
Payment of debt	(4,333)	(2,336)
Issuance of common stock under employee stock plans	716	896
Repurchase of common stock	(1,619)	(10,117)
Excess tax benefit from stock-based compensation	12	163
Cash dividends paid	(1,015)	(844)
Net cash used in financing activities	(3,860)	(1,566)
Increase (decrease) in cash and cash equivalents	3,258	(2,886)
Cash and cash equivalents at beginning of period	8,043	10,929
Cash and cash equivalents at end of period	$11,301	$8,043