Accounting Policies (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Variable Interest Entity [Line Items]
Assets	$ 3,613		$ 3,613		$ 3,108
Liabilities	$ 3,287		$ 3,287		$ 2,819
Weighted average common shares adjustment related to stock-based compensation	1.8	1.9	1.8	2.0
Anti-dilutive potential common shares related to stock-based compensation plans	0.9	1.2	1.2	1.0
Maturities of short term investments			3 months
New collateralized loan obligation temporary warehousing entities [Member]
Variable Interest Entity [Line Items]
Assets	$ 92		$ 92
Liabilities	$ 77		$ 77