Dollars in millions except per share amounts Consolidated Statements of Cash Flows 2019 2018 2017 Operating Activities Net income S 14,975 $ 19.953 $ 29,847 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 28,217 28.430 24,387 Amortization of film and television costs 9.587 3,772 Undistributed earnings from investments in equity affiliates 295 292 174 Provision for uncollectible account 2,575 1,791 .642 Deferred income tax expense (benefit) 1,806 4,931 (15,265) Net (gain) loss from sale of investments, net of impairments (1,218 (739) (282) Pension and postretirement benefit expense (credit) (2,002) 1,148) (1,031) Actuarial (gain) loss on pension and postretirement benefits 5,171 (3.412) 1,258 Asset abandonments and impairments 1,458 46 2,914 Changes in operating assets and liabilities: Receivables 2,812 1,580 (986 Other current assets, inventories and theatrical film and television production costs (12,852) (6,442 (778 Accounts payable and other accrued liabilities (1,524) ,602 316 Equipment installment receivables and related sales 548 (490) (1,239 Deferred customer contract acquisition and fulfillment costs 910) 3,458 (1,422) Postretirement claims and contributions (1,008) (936) (2,064) Other - net 738 990 39 Total adjustments 33,693 23,649 3,163 Net Cash Provided by Operating Activities 48,66 43,60 38,010 Investing Activities Capital expenditures: Purchase of property and equipment (19,435) 20,758) (20,647) Interest during construction "200) 493 903 Acquisitions, net of cash acquired (1,809 43,309) 1,123 Dispositions 4,684 2,148 Purchases), sales and settlement of securities and investments, net 435 (183) 449 Advances to and investments in equity affiliates 365) 1,050 Cash collections of deferred purchase price 50 976 Net Cash Used in Investing Activities (16,690) (63,145) (18,943) Financing Activities Net change in short-term borrowings with original maturities of three months or less (276) (821 Issuance of other short-term borrowings 4,012 4,898 Repayment of other short-term borrowings (6,904) (2,098) Issuance of long-term debt 17,039 41,875 48,793 Repayment of long-term debt (27,592) 52,643 (12,339 Payment of vendor financing (3,050 (560) (572) Issuance of preferred stock 1,164 Purchase of treasury stock (2,417 (609) 463 Issuance of treasury stock 631 745 33 Issuance of preferred interests in subsidiary 7,876 Dividends paid (14,888) 13,410 12,038 Other (678) 3,366) 2,518 Net Cash (Used in) Provided by Financing Activities (25,083) 25,989) 25,930 Net increase (decrease) in cash and cash equivalents and restricted cash 6,895 45,532) 44,997 Cash and cash equivalents and restricted cash beginning of year 5,400 50,932 5,935 65NOTE 7. PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment is summarized as follows at December 31: Lives (years) 2019 2018 Land S 2,651 $ 2, 714 Buildings and improvements 2-44 38,924 38,013 Central office equipment 3-10 96,061 95,173 Cable, wiring and conduit 72,042 73,397 Satellites 2,489 2,961 Other equipment 94,951 93,782 Software 22,244 19,124 Under construction 4,176 5,526 333,538 330,690 Accumulated depreciation and amortization 203,410 199,217 Property, plant and equipment - net S 130,128 $ 131,473 Includes certain network software. Our depreciation expense was $20,285 in 2019, $20,083 in 2018 and $19,761 in 2017. Depreciation expense included amortization of software totaling $3,313 in 2019, $3,092 in 2018 and $2,810 in 2017. 91