* Dollar up 0.41 pct; set for best day in nearly 2 weeks
* Microsoft, Facebook drag down Nasdaq
* Indexes down: Dow 0.08 pct, S&P 0.30 pct, Nasdaq 0.34 pct (Updates to open)
By Yashaswini Swamynathan
Dec 28 (Reuters) - Wall Street slipped for the first time in three days on Wednesday, pulling the Dow away from the elusive 20,000 mark following broad declines across sectors.
The blue-chip index came within 19 points of the psychological milestone shortly after the open. However, losses in shares of Walt Disney and Boeing offset gains in Goldman Sachs.
U.S. equities have been riding a post-election rally, feeding on optimism that Donald Trump's policies would be business friendly, especially to banks and industrials. The rally has also been supported by a spate of strong economic data.
The Dow, which has gained the most among the three major Wall Street indexes from the Trump rally, is on track to have its best yearly gains since 2013. The S&P 500 is set to register a double-digit rise this year, compared with a 0.7 percent decline in 2015.
The dollar index rose 0.41 percent and is on track for its best day since Dec. 15 after strong consumer confidence data on Tuesday lifted sentiment.
At 9:58 a.m. ET (1458 GMT), the Dow was down 15.53 points, or 0.08 percent, at 19,929.51.
The S&P 500 was down 6.86 points, or 0.30 percent, at 2,262.02 and the Nasdaq Composite was down 18.64 points, or 0.34 percent, at 5,468.80.
All 11 major S&P 500 sectors were lower, with technology and consumer staples indexes being the biggest drags.
Microsoft and Facebook weighed the most on the Nasdaq.
Advancing issues outnumbered decliners on the NYSE by 1,558 to 1,028. On the Nasdaq, 1,221 issues rose and 967 fell.
The S&P 500 index showed 10 new 52-week highs and no new lows, while the Nasdaq recorded 48 new highs and six new lows. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)