Page "Key size" Paragraph 17

The Finite Field Diffie-Hellman algorithm has roughly the same key strength as RSA for the same key sizes.

The work factor for breaking Diffie-Hellman is based on the discrete logarithm problem, which is related to the integer factorization problem on which RSA's strength is based.

Thus, a 3072-bit Diffie-Hellman key has about the same strength as a 3072-bit RSA key.