Safety and Clinical Pharmacology of GDC-0068 in Combination With Docetaxel, Fluoropyrimidine Plus Oxaliplatin, Paclitaxel, or Enzalutamide in Participants With Advanced Solid Tumors

Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at screening
* Histologically or cytologically documented advanced or metastatic solid tumors for which established therapy either does not exist or has proven ineffective or intolerable
* Life expectancy greater than or equal to (\>=) 12 weeks
* Adequate hematologic and end organ function
* For female participants of childbearing potential and male participants with partners of childbearing potential, agreement (by participant and/or partner) to use highly effective forms of contraception and to continue its use for the duration of the study and for 4 months after last dose of study treatment (for females) and 6 months after last dose of study treatment (for males)

Exclusion Criteria:

* Prior anti-cancer therapy that fulfills the following criteria: a total of more than three (Arms A and B) or two (Arms C and D) prior cytotoxic chemotherapy regimens, high-dose chemotherapy requiring stem-cell support, and irradiation to \>=25 percent (%) of bone marrow-bearing areas
* Treatment with chemotherapy, hormonal therapy (except hormone replacement therapy, oral contraceptives, or gonadotropin-releasing hormone (GnRH) agonists or antagonists for prostate cancer), immunotherapy, biologic therapy, radiation therapy (except palliative radiation to bony metastases), or herbal therapy as cancer therapy within 4 weeks prior to initiation of ipatasertib. Exceptions are kinase inhibitors approved by local regulatory authorities, which may be used within 2 weeks prior to initiation of ipatasertib, provided that any clinically-relevant drug-related toxicity has completely resolved and prior approval is obtained from the Medical Monitor
* Palliative radiation to bony metastases within 2 weeks prior to initiation of ipatasertib
* History of Type 1 or Type 2 diabetes requiring regular medication
* Grade \>= 2 heart failure or history of unstable angina
* History of clinically significant ventricular arrhythmias or active ventricular arrhythmia requiring medication
* For Arm D only: History of seizure, unexplained loss of consciousness, transient ischemic attack within 12 months of enrollment, cerebral vascular accident, and any brain metastases