Shareholders' Equity (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended				9 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Stock Incentive Plan [Member]	Mar. 31, 2014 Annual Equity Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net of tax unrealized gains (losses) related to credit-only impaired securities	$ 60		$ 60		$ 60	$ 54
Restricted Common Stock, shares issued							102,330
Restricted Common Stock, fair value per share							$ 56.44
Common Stock options issued under stock incentive plan							1,000,000
Common Stock options issued under stock incentive plan, average exercise price			$ 56.47	$ 44.01			$ 56.47
Other benefit plans, shares								84,036
Common Stock issued, fair value per share								$ 57.16
Compensation expense related to stock incentive plans	$ 4	$ 10	$ 18	$ 30