The exact location and time of the service was kept a secret and cameras were banned from the service, reports CNN.
The late singer died last Thursday after a long battle with lung cancer. She was 63.
Since her passing, fans and fellow celebrities have paid their respects to the late celebrities on social media.
E! Online is reporting that tonight's episode of American Idol will feature a robust tribute to the singer's musical legacy with this season's female contestants singing a medley of her greatest hits. The cast will join Gloria Gaynor, Thelma Houston, Gladys Knight, Nelly Furtado, Shelia E. and Jennifer Holiday in the once-of-a-lifetime tribute.
In related news, it was announced that Summer's 1977 hit song "I Feel Love" will be inducted into the National Recording Registry of the Library of Congress.