Equity - Accelerated Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions		1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 07, 2016	Sep. 30, 2016	Dec. 31, 2015	Dec. 07, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 07, 2016
Accelerated Share Repurchases [Line Items]
Total number of shares purchased (in shares)			0.3
Average price paid per share (in dollars per share)			$ 98.98		$ 113.36	$ 99.00	$ 79.06
Accelerated Share Repurchases, September 2016
Accelerated Share Repurchases [Line Items]
Authorized amount								$ 750,000,000
Accelerated share repurchase, settlement (payment) or re		$ (750,000,000)
Total number of shares purchased (in shares)	0.9			6.1
Average price paid per share (in dollars per share)				$ 122.18
Accelerated Share Repurchases, September 2016 | Initial Award
Accelerated Share Repurchases [Line Items]
Total number of shares purchased (in shares)		4.4
Accelerated Share Repurchases, September 2016 | Additional Award
Accelerated Share Repurchases [Line Items]
Total number of shares purchased (in shares)		0.9