Equity Equity (Dividends) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended								12 Months Ended			78 Months Ended
	Dec. 09, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid						$ 0.11			$ 0.11		$ 0.11
Dividends declared on common stock (per share amount)	$ 0.12	$ 0.23	$ 0.11	$ 0.00	$ 0.11	$ 0.21	$ 0.10	$ 0.10	$ 0.00	$ 0.45	$ 0.41	$ 0.25
Treasury Stock, Value, Acquired, Cost Method													$ 1,900
Payments for Repurchase of Common Stock										$ 79	$ 482	$ 308
Acquisition of treasury stock (shares)										8,700,000			154,300,000
Treasury Stock Acquired, Average Cost Per Share													$ 12.12
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 246								$ 246			$ 246
Treasury stock, shares (in shares)		156,878,891				149,037,831				156,878,891	149,037,831		156,878,891