Stockholders' Equity - Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Mar. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Preferred stock, no par value (in USD per share)	$ 0	$ 0
2015 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase			$ 1,800,000,000.00
Series G Preferred Stock
Equity, Class of Treasury Stock [Line Items]
Liquidation preference per share (USD per share)	$ 100,000
Ownership Interest per Depositary Share	0.025%
Series G Preferred Stock, Depository Share
Equity, Class of Treasury Stock [Line Items]
Depositary shares issued (shares)	20,000,000
Liquidation preference per share (USD per share)	$ 25