Capital Transactions (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended							12 Months Ended
	Feb. 06, 2014	May 31, 2013	May 15, 2013	Jun. 01, 2012	May 16, 2012	Aug. 12, 2011	May 11, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Dividends
Dividends per common share (in dollars per share)	$ 0.20							$ 0.19	$ 0.18	$ 0.165
Cash dividend payment			$ 212		$ 201		$ 192	$ 216	$ 204	$ 194
Dividend equivalent payment		$ 4		$ 3		$ 2