Microsoft Corporation, Procter & Gamble. By viewing the profile of Deloitte Audit & Accounting LLP, Deloitte Audit & Accounting LLP is the world's leading professional services organization and one of the world's four largest accounting firms. Major customers include Microsoft and Procter & Gamble. Deloitte Audit & Accounting Firm's clients provide a full range of professional services including auditing and assurance, management consulting, risk consulting, financial consulting, taxation and business consulting.