Study of ABT-199 (GDC-0199) in Combination With Azacitidine or Decitabine (Chemo Combo) in Subjects With Acute Myelogenous Leukemia (AML)

* Subjects must have confirmation of Acute Myeloid Leukemia (AML) by WHO criteria and be ineligible for treatment with a standard cytarabine and anthracycline induction regimen due to co-morbidity or other factors. * Subject must have received no prior treatment for AML with the exception of hydroxyurea * Subjects must have Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2 for subjects greater than or equal to 75 years of age, or 0 to 3 for subjects greater than or equal to 60 to 74 years of age * Subject must have adequate kidney and liver function as described in the protocol

* Subject has received treatment with the following hypomethylating agent and/or chemo therapeutic agent for for an antecedent hematologic disorder (AHD) (Subjects may have been treated with other agents for AHD i.e., Myelodysplastic syndrome \[MDS\]) * Subject has history of Myeloproliferative Neoplasm (MPN). * Subject has favorable risk cytogenetics as categorized by the National Comprehensive Cancer Network Guidelines Version 2, 2014 for AML. * Subject has t(8;21), inv(16), t(16;16) or t(15;17) karyotype abnormalities. * Subject has acute promyelocytic leukemia. * Subject has known active central nervous system involvement with AML. * Subject has received a strong and/or moderate CYP3A inducer within 7 days prior to the initiation of study treatment. * Subject has a history of other malignancies prior to study entry, with the exception of: * Adequately treated in situ carcinoma of the cervix uteri or carcinoma in situ of breast; * Basal cell carcinoma of the skin or localized squamous cell carcinoma of the skin; * Previous malignancy confined and surgically resected (or treated with other modalities) with curative intent. * Subject has a white blood cell count \> 25 × 10\^9/L. Note: Hydroxyurea is permitted to meet this criterion.