Financial report context:
item 6 . selected financial data the following table sets forth our selected financial data . the table should be read in conjunction with item 7 and item 8 of this annual report on form 10-k. .

Financial table:
( $ in millions except per share amounts ): sales and service revenues; year ended december 31 2017: $ 7441; year ended december 31 2016: $ 7068; year ended december 31 2015: $ 7020; year ended december 31 2014: $ 6957; year ended december 31 2013: $ 6820
( $ in millions except per share amounts ): goodwill impairment; year ended december 31 2017: 2014; year ended december 31 2016: 2014; year ended december 31 2015: 75; year ended december 31 2014: 47; year ended december 31 2013: 2014
( $ in millions except per share amounts ): operating income ( loss ); year ended december 31 2017: 865; year ended december 31 2016: 858; year ended december 31 2015: 769; year ended december 31 2014: 655; year ended december 31 2013: 512
( $ in millions except per share amounts ): net earnings ( loss ); year ended december 31 2017: 479; year ended december 31 2016: 573; year ended december 31 2015: 404; year ended december 31 2014: 338; year ended december 31 2013: 261
( $ in millions except per share amounts ): total assets; year ended december 31 2017: 6374; year ended december 31 2016: 6352; year ended december 31 2015: 6024; year ended december 31 2014: 6239; year ended december 31 2013: 6190
( $ in millions except per share amounts ): long-term debt ( 1 ); year ended december 31 2017: 1279; year ended december 31 2016: 1278; year ended december 31 2015: 1273; year ended december 31 2014: 1562; year ended december 31 2013: 1665
( $ in millions except per share amounts ): total long-term obligations; year ended december 31 2017: 3225; year ended december 31 2016: 3356; year ended december 31 2015: 3260; year ended december 31 2014: 3562; year ended december 31 2013: 3277
( $ in millions except per share amounts ): net cash provided by ( used in ) operating activities; year ended december 31 2017: 814; year ended december 31 2016: 822; year ended december 31 2015: 861; year ended december 31 2014: 755; year ended december 31 2013: 260
( $ in millions except per share amounts ): free cash flow ( 2 ); year ended december 31 2017: 453; year ended december 31 2016: 537; year ended december 31 2015: 673; year ended december 31 2014: 590; year ended december 31 2013: 121
( $ in millions except per share amounts ): dividends declared per share; year ended december 31 2017: $ 2.52; year ended december 31 2016: $ 2.10; year ended december 31 2015: $ 1.70; year ended december 31 2014: $ 1.00; year ended december 31 2013: $ 0.50
( $ in millions except per share amounts ): basic earnings ( loss ) per share; year ended december 31 2017: $ 10.48; year ended december 31 2016: $ 12.24; year ended december 31 2015: $ 8.43; year ended december 31 2014: $ 6.93; year ended december 31 2013: $ 5.25
( $ in millions except per share amounts ): diluted earnings ( loss ) per share; year ended december 31 2017: $ 10.46; year ended december 31 2016: $ 12.14; year ended december 31 2015: $ 8.36; year ended december 31 2014: $ 6.86; year ended december 31 2013: $ 5.18

Additional report context:
( 1 ) long-term debt does not include the current portion of long-term debt , which is included in current liabilities . ( 2 ) free cash flow is a non-gaap financial measure and represents cash from operating activities less capital expenditures net of related grant proceeds . see liquidity and capital resources in item 7 for more information on this measure. .

Question: what was the return on total assets during 2013?
Answer: 4.2%