{"pre_text": ["f0b7 free cash flow 2013 cash generated by operating activities totaled $ 6.2 billion , reduced by $ 3.6 billion for cash used in investing activities and a 37% ( 37 % ) increase in dividends paid , yielding free cash flow of $ 1.4 billion .", "free cash flow is defined as cash provided by operating activities ( adjusted for the reclassification of our receivables securitization facility ) , less cash used in investing activities and dividends paid .", "free cash flow is not considered a financial measure under accounting principles generally accepted in the u.s .", "( gaap ) by sec regulation g and item 10 of sec regulation s-k and may not be defined and calculated by other companies in the same manner .", "we believe free cash flow is important to management and investors in evaluating our financial performance and measures our ability to generate cash without additional external financings .", "free cash flow should be considered in addition to , rather than as a substitute for , cash provided by operating activities .", "the following table reconciles cash provided by operating activities ( gaap measure ) to free cash flow ( non-gaap measure ) : millions 2012 2011 2010 ."], "post_text": ["[a] effective january 1 , 2010 , a new accounting standard required us to account for receivables transferred under our receivables securitization facility as secured borrowings in our consolidated statements of financial position and as financing activities in our consolidated statements of cash flows .", "the receivables securitization facility is included in our free cash flow calculation to adjust cash provided by operating activities as though our receivables securitization facility had been accounted for under the new accounting standard for all periods presented .", "2013 outlook f0b7 safety 2013 operating a safe railroad benefits our employees , our customers , our shareholders , and the communities we serve .", "we will continue using a multi-faceted approach to safety , utilizing technology , risk assessment , quality control , training and employee engagement , and targeted capital investments .", "we will continue using and expanding the deployment of total safety culture throughout our operations , which allows us to identify and implement best practices for employee and operational safety .", "derailment prevention and the reduction of grade crossing incidents are critical aspects of our safety programs .", "we will continue our efforts to increase rail defect detection ; improve or close crossings ; and educate the public and law enforcement agencies about crossing safety through a combination of our own programs ( including risk assessment strategies ) , various industry programs and local community activities across our network .", "f0b7 network operations 2013 we will continue focusing on our six critical initiatives to improve safety , service and productivity during 2013 .", "we are seeing solid contributions from reducing variability , continuous improvements , and standard work .", "resource agility allows us to respond quickly to changing market conditions and network disruptions from weather or other events .", "the railroad continues to benefit from capital investments that allow us to build capacity for growth and harden our infrastructure to reduce failure .", "f0b7 fuel prices 2013 uncertainty about the economy makes projections of fuel prices difficult .", "we again could see volatile fuel prices during the year , as they are sensitive to global and u.s .", "domestic demand , refining capacity , geopolitical events , weather conditions and other factors .", "to reduce the impact of fuel price on earnings , we will continue seeking cost recovery from our customers through our fuel surcharge programs and expanding our fuel conservation efforts .", "f0b7 capital plan 2013 in 2013 , we plan to make total capital investments of approximately $ 3.6 billion , including expenditures for positive train control ( ptc ) , which may be revised if business conditions warrant or if new laws or regulations affect our ability to generate sufficient returns on these investments .", "( see further discussion in this item 7 under liquidity and capital resources 2013 capital plan. ) ."], "table": [["millions", "2012", "2011", "2010"], ["cash provided by operating activities", "$ 6161", "$ 5873", "$ 4105"], ["receivables securitization facility [a]", "-", "-", "400"], ["cash provided by operating activities adjusted for the receivables securitizationfacility", "6161", "5873", "4505"], ["cash used in investing activities", "-3633 ( 3633 )", "-3119 ( 3119 )", "-2488 ( 2488 )"], ["dividends paid", "-1146 ( 1146 )", "-837 ( 837 )", "-602 ( 602 )"], ["free cash flow", "$ 1382", "$ 1917", "$ 1415"]], "table_ori": [["<i>Millions</i>", "<i>2012</i>", "<i>2011</i>", "<i>2010</i>"], ["Cash provided by operating activities", "$6,161", "$5,873", "$4,105"], ["Receivables securitization facility [a]", "-", "-", "400"], ["Cash provided by operating activities adjusted for the receivables securitizationfacility", "6,161", "5,873", "4,505"], ["Cash used in investing activities", "(3,633)", "(3,119)", "(2,488)"], ["Dividends paid", "(1,146)", "(837)", "(602)"], ["Free cash flow", "$1,382", "$1,917", "$1,415"]]}

Question: what was the change in free cash flow from 2011 to 2012 , in millions?
Evidence:
table_6: millions the free cash flow of 2012 is $ 1382 ; the free cash flow of 2011 is $ 1917 ; the free cash flow of 2010 is $ 1415 ;
Program: subtract(1382, 1917)
Answer:
str_answer: -535
exe_answer: -535