Other Assets (Components of Other Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Other Assets [Abstract]
Accounts receivable	$ 451	$ 388
Interest and dividends receivable	325	241
Other investments	324	180
Deferred tax asset – net	143	145
Prepaid expenses	90	101
Other	75	106
Total other assets	$ 1,408	$ 1,161	[1]

[1] Adjusted for the retrospective adoption of ASU 2015-03. See New Accounting Standards in Note 2 for additional information.