The Fed has reduced its balance sheet by almost $210,000,000,000 so far YTD.

Assets as of Jan 2/19 = $4.058 Trillion

Assets as of May 31/19 = $3.851 Trillion

www.federalreserve.gov/monetarypolicy/bst_recenttrends.htm

This investopedia page explains it very well imo.

h/t NineteenEighty9