additions to property , plant and equipment are our most significant use of cash and cash equivalents . the following table shows capital expenditures related to continuing operations by segment and reconciles to additions to property , plant and equipment as presented in the consolidated statements of cash flows for 2014 , 2013 and 2012: .
what was the average three year cash flow , in millions , from oil sands mining?
as of december 31 , 2014 , we had repurchased a total of 121 million common shares at a cost of $ 4.7 billion , including 29 million shares at a cost of $ 1 billion in the first six months of 2014 and 14 million shares at a cost of $ 500 million in the third quarter of 2013 . see item 8 . financial statements and supplementary data 2013 note 22 to the consolidated financial statements for discussion of purchases of common stock . liquidity and capital resources our main sources of liquidity are cash and cash equivalents , internally generated cash flow from operations , continued access to capital markets , our committed revolving credit facility and sales of non-strategic assets . our working capital requirements are supported by these sources and we may issue commercial paper backed by our $ 2.5 billion revolving credit facility to meet short-term cash requirements . because of the alternatives available to us as discussed above and access to capital markets through the shelf registration discussed below , we believe that our short-term and long-term liquidity is adequate to fund not only our current operations , but also our near-term and long-term funding requirements including our capital spending programs , dividend payments , defined benefit plan contributions , repayment of debt maturities and other amounts that may ultimately be paid in connection with contingencies . at december 31 , 2014 , we had approximately $ 4.9 billion of liquidity consisting of $ 2.4 billion in cash and cash equivalents and $ 2.5 billion availability under our revolving credit facility . as discussed in more detail below in 201coutlook 201d , we are targeting a $ 3.5 billion budget for 2015 . based on our projected 2015 cash outlays for our capital program and dividends , we expect to outspend our cash flows from operations for the year . we will be constantly monitoring our available liquidity during 2015 and we have the flexibility to adjust our budget throughout the year in response to the commodity price environment . we will also continue to drive the fundamentals of expense management , including organizational capacity and operational reliability . capital resources credit arrangements and borrowings in may 2014 , we amended our $ 2.5 billion unsecured revolving credit facility and extended the maturity to may 2019 . see note 16 to the consolidated financial statements for additional terms and rates . at december 31 , 2014 , we had no borrowings against our revolving credit facility and no amounts outstanding under our u.s . commercial paper program that is backed by the revolving credit facility . at december 31 , 2014 , we had $ 6391 million in long-term debt outstanding , and $ 1068 million is due within one year , of which the majority is due in the fourth quarter of 2015 . we do not have any triggers on any of our corporate debt that would cause an event of default in the case of a downgrade of our credit ratings . shelf registration we have a universal shelf registration statement filed with the sec , under which we , as "well-known seasoned issuer" for purposes of sec rules , have the ability to issue and sell an indeterminate amount of various types of debt and equity securities from time to time. .