Share-Based Payments (Details Textual) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2017 USD ($) Plan Increment $ / shares shares		Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2013 Increment	Jun. 30, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award
Shares issued under ESPP		6,200,000
Share-Based Payments (Textual)
Unrecognized compensation cost related to unvested share-based compensation | $		$ 168.0
Weighted-average period to recognize the cost of unvested awards		1 year 11 months
Number of share-based compensation plans pursuant to which awards are currently being made | Plan		3
Number of shares granted under stock options		0		0	0
Total intrinsic value of options exercised | $		$ 3.4		$ 10.4	$ 38.0
Aggregate intrinsic values of options outstanding | $		$ 11.1
Weighted average remaining contractual term for options outstanding		1 year 4 months
Market stock units
Share-based Compensation Arrangement by Share-based Payment Award
Number of equal annual increments | Increment		3				4
Percentage of earnings of the target number of units granted based on actual stock performance (Minimum)		0.00%				0.00%
Percentage of earnings of the target number of units granted based on actual stock performance (Maximum)		200.00%				150.00%
Number of shares granted	[1]	94,000
Number of days for calculation of average closing stock price		30 days				60 days
Total fair value of vested awards | $		$ 31.4		$ 39.3	$ 109.0
Weighted average grant date fair value | $ / shares		$ 382.59	[1]	$ 328.03	$ 493.43
Cash settled performance units
Share-based Compensation Arrangement by Share-based Payment Award
Number of equal annual increments | Increment		3
Percentage of earnings of the target number of units granted based on actual stock performance (Minimum)		0.00%
Percentage of earnings of the target number of units granted based on actual stock performance (Maximum)		200.00%
Number of shares granted	[2]	83,000,000
Number of days for calculation of average closing stock price		30 days				60 days
Cash in settlement of CSPS awards upon vesting | $		$ 16.6		$ 31.9	$ 79.8
Performance units
Share-based Compensation Arrangement by Share-based Payment Award
Number of equal annual increments | Increment		3
Percentage of earnings of the target number of units granted based on actual stock performance (Minimum)		0.00%
Percentage of earnings of the target number of units granted based on actual stock performance (Maximum)		200.00%
Number of shares granted	[2]	40,000,000
Number of days for calculation of average closing stock price		30 days
Cash in settlement of CSPS awards upon vesting | $		$ 11.5		8.1	$ 12.4
PUs converted to share settlements					32,000
Time-vested restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares granted	[3]	464,000
Total fair value of vested awards | $		$ 100.0		$ 104.6	$ 239.7
Weighted average grant date fair value | $ / shares		$ 293.41	[3]	$ 268.52	$ 388.88
Director | Time-vested restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares granted	[3]	11,000
Settlement of PUs | Performance units
Share-based Compensation Arrangement by Share-based Payment Award
PUs converted to share settlements					11,000
Directors Plan
Share-based Compensation Arrangement by Share-based Payment Award
Total number of shares of common stock for issuance		1,600,000
Ratio of total number of shares reserved under the plan		1.5-to-1
2017 Omnibus Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Ratio of total number of shares reserved under the plan		1.5-to-1
Omnibus Plan number of shares authorized							8,000,000
Attainment Of Performance Criteria in 2013 | Market stock units
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares granted	[1]	9,000

[1] MSUs granted in 2017 include approximately 9,000 MSUs issued in 2017 based upon the attainment of performance criteria set for 2013, in relation to awards granted in that year. MSUs granted during 2017 also include awards granted in conjunction with our annual awards made in February 2017 and MSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant. MSUs granted in 2017 reflect an adjustment based upon the final performance multiplier in relation to shares granted in 2016, 2015 and 2014.

[2] CSPUs granted in 2017 include awards granted in conjunction with our annual awards made in February 2017 and CSPUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant. CSPUs granted in 2017 also include CSPUs issued in 2017 based upon the attainment of performance criteria set for 2016 in relation to shares granted in 2016.

[3] RSUs granted in 2017 primarily represent RSUs granted in conjunction with our annual awards made in February 2017 and awards made in conjunction with the hiring of new employees. RSUs granted in 2017 also include approximately 11,000 RSUs granted to our Board of Directors.