Clofarabine or Daunorubicin Hydrochloride and Cytarabine Followed By Decitabine or Observation in Treating Older Patients With Newly Diagnosed Acute Myeloid Leukemia

acute myeloid leukemia with multilineage dysplasia following myelodysplastic syndrome, adult acute megakaryoblastic leukemia (m7), adult acute minimally differentiated myeloid leukemia (m0), adult acute monoblastic leukemia (m5a), adult acute monocytic leukemia (m5b), adult acute myeloblastic leukemia with maturation (m2), adult acute myeloblastic leukemia without maturation (m1), adult acute myeloid leukemia with 11q23 (mll) abnormalities, adult acute myeloid leukemia with del(5q), adult acute myeloid leukemia with inv(16)(p13;q22), adult acute myeloid leukemia with t(16;16)(p13;q22), adult acute myeloid leukemia with t(8;21)(q22;q22)