This is an open-label, multicenter, Phase I, dose-escalation study to assess the safety, tolerability, and pharmacokinetics of orally administered GDC-0941 administered once daily (QD) and twice daily (BID) in the treatment of advanced or metastatic solid tumors.

Inclusion Criteria:

• Participants with histologically documented, incurable, locally advanced or metastatic solid malignancy that has progressed or failed to respond to at least one prior regimen, and who are not candidates for regimens known to provide clinical benefit
• Evaluable or measurable disease per RECIST
• Life expectancy of greater than or equal to (>/=) 12 weeks
• Documented willingness to use an effective means of contraception (for both men and women) while participating in the study

Exclusion Criteria:

• Leptomeningeal disease as the only manifestation of the current malignancy
• History of Type 1 or 2 diabetes mellitus requiring regular medication
• Any condition requiring anticoagulants, such as warfarin, heparin, or thrombolytics
• Malabsorption syndrome or other condition that would interfere with enteral absorption
• Known untreated central nervous system (CNS) malignancies or treated brain metastases that are not radiographically stable for >/=3 months
• Active congestive heart failure or ventricular arrhythmia requiring medication
• Uncontrolled ascites requiring weekly large-volume paracentesis for 3 consecutive weeks prior to enrollment
• Active infection requiring intravenous (IV) antibiotics
• Requirement for any daily supplemental oxygen
• Uncontrolled hypomagnesemia or hypokalemia, defined as values below the lower limit of normal (LLN), or hypercalcemia above the upper limit of normal (ULN) for the institution despite adequate electrolyte supplementation or management
• Clinically significant history of liver disease, including viral or other hepatitis, current alcohol abuse, or cirrhosis
• Known human immunodeficiency virus (HIV) infection
• Any other diseases, active or uncontrolled pulmonary dysfunction, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an investigational drug or that may affect the interpretation of the results or renders the participant at high risk from treatment complications
• Significant traumatic injury within 3 weeks before Day 1
• Major surgical procedure within 4 weeks prior to initiation of study treatment
• Treatment with chemotherapy, hormonal therapy (except gonadotropin releasing hormone [GnRH] agonists or antagonists for prostate cancer), immunotherapy, biologic therapy, or radiation therapy (except palliative radiation to bony metastases) as cancer therapy within 4 weeks prior to initiation of study treatment
• Palliative radiation to bony metastases within 2 weeks prior to initiation of study treatment
• Need for chronic corticosteroid therapy for greater than (>) 7 days