noncontrolling interest, which were partially offset by higher year-on-year working capital requirements. The combination of accounts receivable, inventories and accounts payable increased working capital by $407 million in 2013, compared to increases of $312 million in 2012, primarily driven by year-on-year increases in working capital requirements due to increasing sales. Additional discussion on working capital changes is provided earlier in the “Financial Condition and Liquidity” section.

 

In 2012, cash flows provided by operating activities increased $16 million compared to 2011. The main positive contribution to operating cash flows related to year-on-year increases in net income including noncontrolling interest. 3M was able to achieve this growth in operating cash flow despite contributing an additional $564 million in its pension and postretirement plans when compared to 2011. The combination of accounts receivable, inventories and accounts payable increased working capital by $312 million in 2012, compared to increases of $484 million in 2011.

 

Free Cash Flow (non-GAAP measure):

 

In addition, to net cash provided by operating activities, 3M uses free cash flow as a useful measure of performance and as an indication of the strength of the Company and its ability to generate cash. 3M defines free cash flow as net cash provided by operating activities less purchases of property, plant and equipment (which is classified as an investing activity). Free cash flow is not defined under U.S. generally accepted accounting principles (GAAP). Therefore, it should not be considered a substitute for income or cash flow data prepared in accordance with U.S. GAAP and may not be comparable to similarly titled measures used by other companies. It should not be inferred that the entire free cash flow amount is available for discretionary expenditures. Below find a recap of free cash flow for 2013, 2012 and 2011.

 

Cash Flows from Investing Activities:

  

Investments in property, plant and equipment enable growth across many diverse markets, helping to meet product demand and increasing manufacturing efficiency. Capital spending was $1.665 billion in 2013, compared to $1.484 billion in 2012 and $1.379 billion in 2011. The Company expects 2014 capital spending to be approximately $1.7 billion to $1.8 billion, as 3M continues to invest in its businesses. In 2013, 3M continued its expansion of manufacturing capacity in key growth markets, including investments in the U.S., China, Germany, and Brazil. This included significant investments across 3M’s many businesses, such as abrasives, industrial adhesives and tapes, advanced materials, electronics-related, infection prevention, and other businesses. 3M continued its investments in IT systems and infrastructure, including ongoing phased implementation of an ERP system on a worldwide basis over the next several years. In addition, 3M is sustaining existing facilities through general maintenance, cost reduction, and compliance efforts. In 2012, 3M expanded manufacturing capacity in key growth markets, particularly with respect to international and emerging market countries. This included