Interest expense increased $12 million, primarily due to higher weighted-average debt outstanding and hedge ineffectiveness on our interest rate swap.
(1) See Note 3, "INVESTMENTS IN EQUITY INVESTEES," to the Consolidated Financial Statements for additional information.
(2) See Note 19, "ACQUISITIONS," to the Consolidated Financial Statements for additional information.
Our income tax rates are generally less than the 35 percent U.S. statutory income tax rate, primarily because of lower taxes on foreign earnings and research tax credits. On December 22, 2017, the U.S. enacted the Tax Cuts and Jobs Act. Our effective tax rate for 2017 was 58.0 percent compared to 24.6 percent for 2016. The impacts of the Tax Legislation resulted in additional income tax expense of $781 million to our tax provision (excluding the noncontrolling interest and equity investee adjustments). See Note 4, "INCOME TAXES," to our Consolidated Financial Statements for additional information.
Noncontrolling interests in income of consolidated subsidiaries decreased $67 million, primarily due to the $43 million impact of Tax Legislation on Cummins India Ltd. regarding withholding taxes on foreign earnings, the acquisition of the remaining interest in Wuxi Cummins Turbo Technologies Co. Ltd. in the fourth quarter of 2016 and elimination of the net loss for the automated transmission business.
Net income and diluted earnings per share attributable to Cummins Inc. decreased $395 million and $2.26 per share, respectively, primarily due to the $777 million impact of Tax Legislation, increased selling, general and administrative expenses and higher research, development and engineering expenses, partially offset by higher net sales and gross margin, lower charges for a loss contingency and higher equity, royalty and interest income from investees. Diluted earnings per share for 2017 was negatively impacted $4.65 per share due to the Tax Legislation, partially offset by a benefit of $0.04 per share from fewer weighted-average shares outstanding, primarily due to purchases under the stock repurchase program. See Note 4, "INCOME TAXES," to our Consolidated Financial Statements for additional information.