David Pastrnak and Matt Grzelcyk each had a goal and an assist, and Pavel Zacha had two assists for the Bruins (50-10-5), who have lost two of three. Jeremy Swayman made 21 saves.
Boston remained 17 points ahead of the Toronto Maple Leafs for first in the Atlantic Division.
"I think Detroit outskated us and outworked us," Bruins coach Jim Montgomery said. "I didn't think we had the compete level to win one-on-one puck battles in the first two periods."
Alex Chiasson gave the Red Wings a 1-0 lead at 12:22 of the first period, tapping in a rebound for a power-play goal.
Seider made it 2-0 at 6:34 of the second period with a short-handed goal. He stole the puck from Pastrnak at the blue line before skating in and scoring with a backhand on a breakaway.
"In our system, I'm pressuring the entry, and I saw I had a chance to force something there," Seider said. "I had some pressure on my forehand side, so I went backhand. Luckily, I got it over his glove, because that's not a shot I practice every day."