Kramer vs. Kramer ending explained

What happens

After winning custody, Joanna comes to Ted's apartment and admits Billy's real home is with him. She asks to go up and tell Billy herself. Ted waits with her in the lobby as the elevator doors close.

The last image

Ted and Joanna stand together in the lobby as the elevator doors close on her way up to Billy.

What it says

Joanna gives up the custody she won because she sees what Ted's daily care has built. The film refuses a winner: one parent's loss is the other's gain, and the ending lets love, not the court, decide.