Billionaire Mukesh Ambani-led Reliance Industries has completed the merger of its media assets with the India business of global media house Walt Disney and formed a joint venture with a valuation of over Rs 70,000 crore.The JV will be one of the largest media and entertainment companies in India with a combined revenue of approximately Rs 26,000 crore and will be led by Nita Ambani as its chairperson, according to a joint statement.