Sources of Funds The following table presents the sources of our cash and cash equivalents for the years ended December 31, 2016, 2015 and 2014. See Notes 12, 14 and 16 of the notes to our consolidated financial statements included in Item 8 of this report for further discussion of divestitures of oil and natural gas assets, investments and other assets, respectively.
Cash provided by (used in) operating activities ......................................... Proceeds from issuance of term loan ........................................................ Proceeds from long-term debt, net ............................................................ Proceeds from oilfield services long-term debt, net ................................... Divestitures of proved and unproved properties ........................................ Sales of other property and equipment ..................................................... Proceeds from sales of investments .......................................................... Other ......................................................................................................... Total sources of cash and cash equivalents.......................................
Years Ended December 31, 2016 2015 2014 ($ in millions) $ (204) $ 1,234 $ 4,634 1,476 — — 2,210 — 2,966 — — 888 1,406 189 5,813 131 89 1,003 — — 239 — 52 37 $ 5,019 $ 1,564 $ 15,580
Cash used in operating activities was $204 million in 2016 compared to cash provided by operating activities of $1.234 billion in 2015 and $4.634 billion in 2014. The decrease is primarily the result of lower realized prices for the oil and natural gas we sold in addition to lower volumes of oil, natural gas and NGL sold, partially offset by decreases in certain of our operating expenses. Changes in cash flow from operations are largely due to the same factors that affect our net income, excluding various non-cash items such as depreciation, depletion and amortization, impairments, gains or losses on sales of fixed assets, deferred income taxes and mark-to-market changes in our derivative instruments. See further discussion below under Results of Operations. The following table reflects the proceeds received from issuances of debt in 2016, 2015 and 2014. See Note 3 of the notes to our consolidated financial statements included in Item 8 of this report for further discussion.
Convertible senior notes................. Senior notes(a) ................................ Term loans(a) ................................... Total .......................................
Years Ended December 31, 2016 2015 2014 Principal Principal Principal Amount Amount Amount of Debt Net of Debt Net of Debt Net Issued Proceeds Issued Proceeds Issued Proceeds ($ in millions) 1,250 $ $ 1,235 $ — $ — $ — $ — 1,000 975 — — 3,500 3,460 1,500 1,476 — — 400 394 3,750 $ $ 3,686 $ — $ — $ 3,900 $ 3,854
___________________________________________ (a)
Our 2015 debt exchange of certain outstanding unsecured senior notes and contingent notes for Second Lien Notes did not result in any additional debt issued or proceeds received. The 2014 amounts include debt issued in connection with the spin-off of our oilfield services business. All deferred charges and debt balances related to the spin-off were removed from our consolidated balance sheet as of June 30, 2014. See Note 13 of the notes to our consolidated financial statements included in Item 8 of this report for further discussion of the spin-off.
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