EQUITY AND STOCK-BASED COMPENSATION - Restricted Stock Share and Restricted Stock Unit Awards (Details) - Restricted stock shares and restricted stock units
$ / shares in Units, shares in Thousands, $ in Millions
9 Months Ended
Oct. 01, 2016
USD ($)
$ / shares
shares
Weighted-Average Grant-Date Fair Value Per Share  
Unrecognized compensation cost | $ $ 16.1
Weighted-average period cost expected to be recognized 1 year 9 months 4 days
SPX  
Unvested Restricted Stock Shares and Restricted Stock Units  
Outstanding at beginning of year (in shares) | shares 1,128
Granted (in shares) | shares 731
Vested (in shares) | shares (303)
Forfeited and other (in shares) | shares (353)
Outstanding at the end of period (in shares) | shares 1,203
Weighted-Average Grant-Date Fair Value Per Share  
Outstanding at beginning of year (in dollars per share) | $ / shares $ 51.13
Granted (in dollars per share) | $ / shares 27.99
Vested (in dollars per share) | $ / shares 54.78
Forfeited and other (in dollars per share) | $ / shares 40.49
Outstanding at the end of period (in dollars per share) | $ / shares $ 38.77