Supplemental Disclosures (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred and contingent purchase consideration from prior years' acquisition	$ 98	$ 49	$ 55
Deferred purchase consideration from prior years' acquisitions	54	36	25
Contingent purchase consideration from prior years' acquisitions	44	13	30
Net charge for adjustments related to acquisitions	9	45	31
Payment of contingent consideration	42	34	12
Non-cash issuance of common stock	73	72	108
Stock-based compensation expense, equity awards	$ 87	67	$ 75
Putnam
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash used in operating activities, discontinued operations		$ 82