Defined Contribution and Deferred Compensation Plans (Expenses for deferred compensation plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employees [Member]
Expenses for deferred compensation plans [Abstract]
Employer matching contributions	$ 10	$ 9	$ 7
Increase (decrease) in measurement of liabilities, net of total return swap	5	14	7
Total plan expense (income)	15	23	14
Agents [Member]
Expenses for deferred compensation plans [Abstract]
Employer matching contributions	2	1	1
Increase (decrease) in measurement of liabilities, net of total return swap	2	4	2
Total plan expense (income)	$ 4	$ 5	$ 3