Business Development - Schedule of Business Acquisition (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 01, 2015	Nov. 01, 2013
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 9,314	$ 24	$ 204
Goodwill, Acquired During Period		508	12
Goodwill	$ 14,480	14,480	$ 13,978	$ 13,978
GE Healthcare [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		8,900
Cash Acquired from Acquisition	$ 177
Business Combination, Acquired Loan portfolios					$ 8,300
Business Combination, Acquired Intangibles					136
Goodwill, Acquired During Period		$ 500
Business Combination, Total Assets Acquired					$ 9,200
Beech Street Capital [Member]
Business Acquisition [Line Items]
Business Combination, Value of Acquired Mortgage Servicing Portfolio						$ 10,000