Comparison of NN1250 With Insulin Glargine in Subjects With Type 2 Diabetes

Inclusion Criteria: * Type 2 diabetes (diagnosed clinically) for at least 6 months * Insulin naïve subjects (allowed are: previous short term insulin treatment up to 14 days; treatment during hospitalisation or during gestational diabetes is allowed for periods longer than 14 days) * Current treatment: metformin monotherapy or metformin in any combination with insulin secretagogues (sulphonylurea (SU) or glinide), DPP-4 inhibitor, alpha-glucosidase-inhibitor (acarbose) with unchanged dosing for at least 3 months prior to visit 1 with the minimum doses stated: -Metformin: alone or in combination (including fixed combination) 1500 mg daily or maximum tolerated dose (at least 1000 mg daily)-Insulin secretagogue (sulfonylurea (SU) or glinide): minimum half of the daily maximal dose according to local labelling -DPP-4 inhibitor: minimum half of the daily maximal dose according to local labelling -alpha-glucosidase-inhibitor (acarbose): minimum half of the daily maximal dose or maximum tolerated dose * HbA1c 7.0-10.0 % (both inclusive) by central laboratory analysis * BMI (Body Mass Index) below or equal to 45.0 kg/m\^2 Exclusion Criteria: * Use within the last 3 months prior to Visit 1 of: Thiazoledinediones (TZDs), Exenatide or Liraglutide * Cardiovascular disease, within the last 6 months prior to visit 1, defined as: stroke; decompensated heart failure New York Heart Association (NYHA) class III or IV; myocardial infarction; unstable angina pectoris; or coronary arterial bypass graft or angioplasty * Uncontrolled treated/untreated severe hypertension (systolic blood pressure at least 180 millimetre (mm) mercury (Hg) and/or diastolic blood pressure at least 100 mmHg) * Pregnancy, breast-feeding, the intention of becoming pregnant or not using adequate contraceptive measures according to local requirements * Cancer and medical history of cancer hereof (except basal cell skin cancer or squamous cell skin cancer)